Multi-wire saw yield device and method

Abstract

A kind of multi-wire cutting retreat device and method, device: bottom sacrificial pad is bonded to the bottom end of the entry side of the ingot to be cut, and is located above the cutting wire net of multi-wire cutting machine;Comb assembly includes comb seat and multiple comb strips installed in comb seat upper end in length direction sequentially interval, comb assembly is horizontally arranged below the feed path of the ingot to be cut, simultaneously, multiple comb strips are located below multiple cutting lines in cutting wire net, and multiple comb strips and multiple cutting lines are distributed one by one in upper and lower;Constant force synchronous retreat mechanism is vertically arranged below comb assembly, it has telescopic support rod, and the upper end of telescopic support rod is connected with the lower end of comb seat.Method: preset and standby stage;Self-guided passive insertion stage;Relative physical limit stage;Long-stroke constant force synchronous retreat stage.The present application can realize reliable protection to wafer cutting whole process, and can effectively ensure the cutting quality of wafer.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor technology, specifically relating to a multi-wire cutting retraction device and method. Background Technology

[0002] In the multi-wire dicing process of large-size wafers, especially silicon carbide (SiC) wafers, the industry generally adopts a bottom-up dicing method that uses a mixture of carrier liquid and diamond particles in a free abrasive slurry, and a spindle to drive the ingot downwards to feed it.

[0003] As wafer processing moves towards thinner profiles and ultra-narrower kerfs, the shortcomings of existing processes are becoming increasingly apparent. The core issue is the lever-type shearing edge chipping problem caused by the adsorption of slurry liquid film. Specifically, after the bottom of the ingot is cut open, adjacent wafers adhere tightly to each other within the ultra-narrow kerf due to the surface tension and capillary action of the high-viscosity slurry. The tiny closed displacement generated at the bottom of the wafer is transmitted upwards based on the rigid body characteristics, forming a lever effect at the top of the incompletely cut-out end, generating a large shear load. When the metal wire cuts through the exit end, the wire bow rebound and the sudden release of the load are superimposed, which can easily induce severe edge chipping at the top of the wafer.

[0004] The aforementioned phenomena have become a common problem restricting the improvement of yield in multi-wire dicing of large-size wafers. Currently, the industry still lacks mature hardware solutions that can reliably weaken or even completely block edge breakage induced by liquid film adsorption without disturbing the complex and harsh dicing flow field. To solve these technical problems, there is an urgent need to provide a multi-wire dicing retraction device and method. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a multi-wire cutting retraction device and method. This device boasts significant advantages such as simplified structure, passive self-adaptation, high reliability under harsh flow conditions, and low manufacturing cost. It provides reliable protection throughout the entire wafer cutting process, effectively ensuring wafer cutting quality and simultaneously improving cutting efficiency. The method is simple to implement and low in cost. It constructs a mechanically coordinated cutting scheme that utilizes a bottom sacrificial pad for isolation and protection, a comb-tooth rack for passive flow guidance support, and constant force synchronous retraction. This effectively solves the industry pain point of edge chipping due to adsorption in large-size wafer cutting, significantly improving both wafer cutting quality and efficiency.

[0006] To achieve the above objectives, the present invention provides a multi-wire cutting retraction device, comprising: Bottom sacrificial pad, which is bonded to the bottom end of the inlet side of the ingot to be cut and located above the cutting wire mesh of the multi-wire cutting machine; The comb assembly includes a comb base and multiple comb strips that are sequentially and spaced apart on the upper end of the comb base along the length direction. The comb assembly is horizontally positioned below the feed path of the ingot to be cut. At the same time, the multiple comb strips are located below multiple tangents in the cutting wire mesh, and the multiple comb strips are distributed one-to-one with the multiple tangents. A constant force synchronous yielding mechanism is vertically arranged below the comb assembly. It has a telescopic support rod, and the upper end of the telescopic support rod is connected to the lower end of the comb seat to provide a constant support force.

[0007] Furthermore, to ensure the stability of the connection, the bottom sacrificial pad is bonded to the ingot to be cut using high-hardness slicing adhesive.

[0008] Furthermore, to avoid ingot damage during operation, and to ensure sand removal efficiency and effectiveness, the height of the comb teeth does not exceed the thickness of the bottom sacrificial pad, and its thickness is less than the size of the nominal cutting kerf.

[0009] Furthermore, to improve the sand removal effect and efficiency, the top of the comb teeth is provided with a wedge-shaped, bullet-shaped, or large arc-shaped flow guiding structure. This flow guiding structure creates a flow guiding surface at the top of the comb teeth, facilitating the gentle removal of high-viscosity mortar.

[0010] Furthermore, in order to balance rigidity and non-destructive contact under extremely thin working conditions, the comb teeth are made of wear-resistant polymer engineering plastic, or a composite structure of a rigid metal sheet skeleton and a flexible anti-scratch coating on the surface.

[0011] Furthermore, in order to directly utilize the comb tooth holder to provide a limiting protection function, the upper surface of the comb tooth holder is a planar structure and serves as a height reference surface.

[0012] Furthermore, in order to provide a constant supporting force or lifting force to ensure stability during the cutting process, the constant force synchronous retraction mechanism includes a precision low-friction cylinder and a high-precision proportional pressure regulating valve. The telescopic support rod is the piston rod of the precision low-friction cylinder. The high-precision proportional regulating valve is used to establish an air circuit connection between the high-pressure air source and the precision low-friction cylinder, and to control the movement of the high-precision low-friction cylinder.

[0013] In this invention, a one-to-one physical isolation structure between the comb assembly and the cutting wire mesh is used to prevent capillary adhesion and edge breakage from the mechanical source. The device employs multiple equidistant comb bars, precisely matched to the spacing of the cutting wire mesh, to ensure a one-to-one correspondence with the multiple tangential lines. During the cutting process, each comb bar precisely enters the kerf of the bottom sacrificial pad by tracking its corresponding tangential line, utilizing its geometric barrier properties to form a stable one-to-one physical isolation barrier within the kerf. This barrier forcibly blocks the capillary adhesion effect generated by high-viscosity slurry in the narrow kerf, eliminating the tendency of adjacent wafers to move inward due to liquid film adhesion. It mechanically blocks the lever shear stress generated by displacement transmission to the top exit point, fundamentally solving the industry problem of edge breakage due to adhesion in large-size wafer cutting. Simultaneously, the bottom sacrificial pad, in conjunction with the comb assembly with a limiting surface, achieves non-destructive isolation of the wafer body throughout the cutting process. The device adheres a bottom sacrificial pad to the bottom end of the ingot on the cutting side, serving as a safe isolation zone for the comb bar insertion, replacing the wafer body in bearing the physical contact with the comb bar. Meanwhile, the upper surface of the comb holder serves as a height reference surface, strictly limiting the physical opening action of the comb bar within the sacrificial pad. Thus, when the top surface of the comb holder is fully in contact with the bottom surface of the sacrificial pad, the comb bar reaches its maximum insertion depth without touching the ingot body above. Throughout the entire cutting cycle, the comb bar and the wafer body maintain zero contact, effectively blocking the adsorption shear force and completely eliminating the risk of scratches and microcracks caused by slurry extrusion on the wafer surface in traditional comb insertion schemes. This provides a reliable structural guarantee for improving the yield of large-size wafer cutting. Simultaneously, a constant force synchronous retraction mechanism is employed to eliminate the accumulation of internal stress in the reverse thrust with a constant supporting force unaffected by the stroke. This device features a constant force synchronous retraction mechanism below the comb assembly, centered on a precision low-friction cylinder and a high-precision proportional pressure regulating valve. The proportional pressure regulating valve precisely controls the cylinder's air supply pressure, allowing the telescopic support rod to apply a stable upward constant supporting force to the comb assembly. This constant force, during the long-stroke deep cutting of large-size wafers, does not increase or decrease in support force with the increase of the retraction stroke, breaking through the mechanical limitation of conventional elastic support components that "the deeper the compression, the greater the rebound force." This design ensures that the comb teeth always maintain a constant force to stably open the sacrificial pad kerf to effectively block capillary adhesion forces, and fundamentally avoids the upward transmission of the internal stress accumulated with the feed stroke, which could cause brittle wafer extrusion deformation and fracture, thus fully guaranteeing the core surface quality of the wafer after cutting. At the same time, the whole adopts a purely passive mechanical adaptive closed-loop architecture, achieving high reliability operation without electronic control. This device uses a completely mechanical structure to achieve adaptive closed-loop function, without the need for electronic components such as sensors, controllers, or servo motors. It cleverly utilizes the Z-axis feed power of the multi-wire cutting machine spindle to smoothly complete the coordinated action of "self-guided insertion" and "equal depth synchronous retraction" of the comb teeth relative to the ingot.This purely passive mechanical adaptive design not only avoids the potential risks of electrical control signal delay and electromechanical interference, but also demonstrates excellent operational reliability in harsh flow environments filled with high-viscosity slurry. Simultaneously, the device boasts a simplified structure, low manufacturing cost, minimal modification difficulty, and convenient maintenance, making it highly valuable for industrial mass production. Furthermore, the bottom sacrificial pad, comb assembly, and constant-force synchronous retreat mechanism work in tandem to form a complete closed-loop wafer protection function. The device provides a safe isolation zone on the cutting side through the bottom sacrificial pad, performs physical opening of the kerf and slurry drainage through the comb assembly, and provides a constant, stroke-independent support force for passive follow-and-retreat. These three components are structurally progressive and functionally interconnected, forming a complete mechanical protection closed loop encompassing isolation protection, physical opening, and constant-force follow-and-retreat. No additional control signals are required between the components; they automatically coordinate through structural cooperation, completely preventing lever shearing and edge chipping caused by liquid film adsorption from the mechanical source, achieving comprehensive, non-destructive protection of the wafer throughout the entire process.

[0014] This device has significant advantages such as simplified structure, passive self-adaptation, high reliability under harsh flow fields, and low manufacturing cost. It can provide reliable protection for the entire wafer dicing process, effectively ensure the dicing quality of wafers, and at the same time, effectively improve the dicing efficiency of wafers.

[0015] The present invention also provides a multi-line cutting yielding method, which employs a multi-line cutting yielding device and includes the following steps: Step 1: Preset and Waiting Phase; In the initial cutting stage, the constant force synchronous yielding mechanism is activated, and the comb assembly is pushed up to the preset height in the feed path using the telescopic support rod; the constant upward support force of the constant force synchronous yielding mechanism is set, and the comb assembly is stably maintained at the preset height by the telescopic support rod, so that the comb assembly is in a static waiting state. Step 2: Self-guided passive insertion phase; The ingot, with a bottom sacrificial pad attached, is slowly fed from top to bottom by the main shaft. Multiple tangents in the cutting wire mesh cut into the bottom sacrificial pad and form multiple slits at the bottom of the bottom sacrificial pad. As the ingot continues to descend, multiple comb teeth follow behind the multiple tangents and enter the multiple slits. Through the guiding effect, the high-viscosity sand entering the slits is discharged in real time, and the slits are kept open to prevent the formation of capillary adhesion. Step 3: Relative physical limit stage; As the ingot continues to feed downwards, when the upper surface of the comb tooth holder is in complete contact with the bottom sacrificial pad, the comb tooth reaches its maximum insertion depth. The comb tooth assembly and the bottom sacrificial pad achieve relative physical limitation. At the same time, multiple comb tooth strips form a one-to-one physical isolation barrier with multiple cuts without contacting the ingot above. Step 4: Long-stroke constant force synchronous yielding stage; After achieving relative physical limitation, the spindle continues to drive the ingot to perform full-stroke depth cutting. During the full-stroke depth cutting operation, the downward feed thrust forces the comb assembly to remain in the maximum insertion state and simultaneously retract downwards. During the continuous compression and exhaust of the precision low-friction cylinder, the air supply pressure is adjusted in real time using a high-precision proportional pressure regulating valve to ensure that the upward constant support force is always maintained within the initially set constant range until the ingot cutting operation is completed.

[0016] Compared with the prior art, the present invention has the following technical advantages: 1. This method utilizes a four-stage mechanical closed loop—pre-set waiting, self-guided passive insertion, relative physical limiting, and long-stroke constant force retreat—to prevent adsorption-induced edge breakage from the mechanical source. The method constructs four sequentially connected process stages: First, the comb assembly is pre-positioned at a preset height in the feed path and set with constant force support, remaining in a static waiting state. As the ingot descends, the comb teeth are self-guided into the sacrificial pad kerf using the Z-axis feed power of the main shaft, simultaneously discharging slurry and widening the kerf to block capillary adsorption. When the top surface of the comb seat is in contact with the bottom surface of the sacrificial pad, relative physical limiting is achieved, forming a one-to-one physical isolation barrier between the comb teeth and the kerf. Finally, under constant force support, a long-stroke synchronous retreat is completed until the cutting is finished. This method relies on pure mechanical linkage rather than electronic control, achieving a fully automated protection closed loop from pre-setting to cutting completion, preventing lever shear edge breakage caused by liquid film adsorption from the process source.

[0017] 2. This method employs a process sequence where the sacrificial pad is cut first, and the comb tooth is inserted into the kerf following its insertion, ensuring that the wafer body is protected from physical contact damage throughout the entire cutting process. The cutting process sequence is precisely designed: the cutting line first cuts into the bottom sacrificial pad bonded to the bottom of the ingot's entry point. After forming a kerf inside the pad, the comb tooth follows the cutting line into the kerf area, and the insertion depth of the comb tooth is strictly limited within the thickness of the pad using the comb tooth holder's limiting surface. This process sequence of cutting the pad first, inserting the comb tooth, and stopping at the pad ensures that at any stage of the entire cutting cycle, the comb tooth only has physical contact with the sacrificial pad, maintaining zero contact with the wafer body. This method completely avoids the process defect of comb teeth scratching the wafer surface in traditional comb insertion schemes, providing a reliable process-level guarantee for wafer surface quality.

[0018] 3. A constant-force passive following yielding method is adopted, replacing the traditional elastic variable-force support with a constant support force independent of stroke. In the long-stroke depth cutting stage, this method uses a constant-force passive following yielding method based on a precision low-friction cylinder and a proportional pressure regulating valve: as the ingot continues to feed downwards, forcing the comb assembly to yield synchronously, the cylinder is compressed and exhausts air. Simultaneously, the high-precision proportional pressure regulating valve adjusts the air supply pressure in real time, ensuring that the upward constant support force remains within the initial set range and does not increase with the increase of the yielding stroke. This method overcomes the process bottlenecks of traditional elastic support schemes, where the support force increases linearly with the compression amount and the counter-thrust force at the end of a long stroke is too large. It ensures that the comb rack always stably supports the kerf with a constant force to block capillary adhesion, and fundamentally avoids the extrusion deformation and fracture of brittle wafers caused by the destructive internal stress accumulated with the feed stroke. It is suitable for the long-stroke processing requirements of deep cutting of large-size wafers.

[0019] 4. Utilizing the flow-guiding structure of the comb teeth in conjunction with the passive insertion action, mortar discharge and capillary adsorption blocking are simultaneously completed within the cut. During the passive insertion of the comb teeth into the cut, the wedge-shaped, bullet-shaped, or large arc-shaped flow-guiding structure at the top of the comb teeth gently and in real time discharges the high-viscosity mortar from the cut, while simultaneously maintaining the physical open state of the cut to disrupt the capillary structure. This method combines the sand-discharging and opening functions of the comb teeth into one, completed simultaneously in the same passive insertion action. No additional sand-discharging device or operating steps are required, resulting in a simple and efficient process that effectively avoids secondary wire clamping failures caused by mortar accumulation and drying / curing in the cut.

[0020] 5. The method relies entirely on the universal Z-axis feed power of the machine tool spindle, requiring no additional drive source. This results in low process modification costs and strong adaptability. All core actions of this method—passive insertion of the comb rack, synchronous retraction, and sand guiding and removal—are driven by the downward Z-axis feed motion of the multi-wire EDM machine tool spindle, without relying on independent servo drives, sensor feedback, or CNC linkage systems. Therefore, this method can achieve process upgrades simply by adding a retraction device without altering the existing machine tool structure or adding an electrical control system. It boasts low modification costs, a short implementation cycle, strong adaptability, and good versatility across different models of multi-wire EDM equipment, making it highly valuable for industrial application.

[0021] This method is simple to implement and has low implementation costs. It constructs a mechanical collaborative cutting scheme with bottom sacrificial pad isolation protection, passive insertion of comb toothed rack for flow guidance support, and constant force synchronous yielding. It not only effectively solves the industry pain point of adsorption and edge breakage in large-size wafer cutting, but also overcomes the technical deviations of conventional solutions in this field, and can effectively improve the cutting quality and efficiency of wafers. Attached Figure Description

[0022] Figure 1This is a schematic diagram showing the state of the retraction device in the preset and waiting stages in this invention; Figure 2 This is a schematic diagram of the retraction device in the self-guided passive insertion stage of the present invention; Figure 3 This is a schematic diagram showing the state of the retraction device in the relative physical limiting stage in this invention; Figure 4 This is a schematic diagram of the retraction device in the long-stroke constant force synchronous retraction stage of the present invention.

[0023] In the figure: 1. Constant force synchronous retraction mechanism, 2. Comb tooth assembly, 3. Comb tooth seat, 4. Comb tooth strip, 5. Bottom sacrificial pad, 6. Ingot, 7. Tangent line, 8. Cut seam. Detailed Implementation

[0024] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0025] like Figures 1 to 4 As shown, the present invention provides a multi-line cutting retraction device, comprising: Bottom sacrificial pad 5 is bonded to the bottom end of the cutter side of the ingot 6 to be cut and is located above the cutting wire mesh of the multi-wire cutting machine; The comb assembly 2 includes a comb base 3 and multiple comb strips 4 that are sequentially and spaced apart on the upper end of the comb base 3 along the length direction. The comb assembly 2 is horizontally positioned below the feed path of the ingot 6 to be cut. At the same time, the multiple comb strips 4 are located below multiple tangent lines 7 in the cutting wire mesh, and the multiple comb strips 4 are distributed in a one-to-one correspondence with the multiple tangent lines 7. As another implementation, the comb bar 4 in the comb assembly 2 can be replaced with a micro roller, micro roller or micro bearing structure, and can be rotated horizontally on the central axis. In this way, during the pressing of the ingot 6, the original sliding friction can be converted into rolling friction, which can further reduce the squeezing resistance of the bottom sacrificial pad 5, and further improve the sand removal efficiency and effect.

[0026] A constant force synchronous retraction mechanism 1 is vertically arranged below the comb assembly 2. It has a telescopic support rod, and the upper end of the telescopic support rod is connected to the lower end of the comb seat 3. It is used to provide a constant upward support force to the comb assembly 2. This constant support force does not increase or decrease as the downward retraction stroke of the comb assembly 2 increases.

[0027] To ensure the stability of the connection, the bottom sacrificial pad 5 is bonded to the ingot 6 to be cut with high-hardness slicing adhesive.

[0028] To avoid ingot damage, the height of the comb 4 does not exceed the thickness of the bottom sacrificial pad 5, and its thickness is less than the size of the nominal cut slit 8. Furthermore, it is best to leave a sand removal gap of 10-20 micrometers between the comb 4 and the cut slit 8, which can effectively prevent the occurrence of extrusion and cracking while ensuring the sand removal effect and efficiency.

[0029] To improve the sand removal effect and efficiency, the top of the comb bar 4 is provided with a wedge-shaped, bullet-shaped, or large arc-shaped flow guiding structure so as to gently remove high-viscosity mortar.

[0030] To balance rigidity and non-destructive contact under extremely thin working conditions, the comb bar 4 is made of wear-resistant polymer engineering plastics (such as EEK, POM), or a composite structure of a rigid metal sheet skeleton and a flexible anti-scratch coating on the surface.

[0031] In order to directly utilize the comb tooth seat to provide a limiting protection function, the upper end surface of the comb tooth seat 3 is a planar structure and serves as a height reference surface limiting step.

[0032] To provide a constant supporting or lifting force to ensure stability during the cutting process, the constant force synchronous retraction mechanism 1 includes a precision low-friction cylinder and a high-precision proportional pressure regulating valve. The telescopic support rod is the piston rod of the precision low-friction cylinder. The high-precision proportional pressure regulating valve is used to establish an air circuit connection between the high-pressure air source and the precision low-friction cylinder, and to control the movement of the high-precision low-friction cylinder. In actual production, a constant air source pressure with a set low threshold, such as providing a thrust of 2-5N, can be set through the high-precision proportional pressure regulating valve, so that the precision low-friction cylinder can output a constant but variable supporting or lifting force upwards under any compression stroke.

[0033] As an alternative, the constant force synchronous retraction mechanism 1 can also adopt an active electronic control device, such as a servo motor or linear motor with a torque sensor (force feedback control). In this way, when the machine tool spindle is pressed down, the motor can passively reverse and retract in a constant torque / constant thrust mode to provide constant support force for the comb assembly 2.

[0034] This invention has significant advantages such as simplified structure, passive self-adaptation, high reliability under harsh flow fields, and low manufacturing cost. It can provide reliable protection for the entire wafer cutting process, effectively ensure the cutting quality of wafers, and effectively improve the cutting efficiency of wafers.

[0035] The present invention also provides a multi-line cutting yielding method, which employs a multi-line cutting yielding device and includes the following steps: Step 1: Preset and Waiting Phase; In the initial cutting stage, the constant force synchronous retraction mechanism 1 is activated, and the comb assembly 2 is pushed up to a preset height in the feed path using the telescopic support rod; a constant upward support force is set for the constant force synchronous retraction mechanism 1, and the comb assembly 2 is stably maintained at the preset height by the telescopic support rod, so that the comb assembly 2 is in a static waiting state, such as... Figure 1 As shown; Step 2: Self-guided passive insertion phase; The ingot 6, with the bottom sacrificial pad 5 attached, is slowly fed downwards by the spindle. Multiple tangents 7 in the cutting wire mesh first cut into the bottom sacrificial pad 5, forming multiple slits 8 at the bottom of the pad 5. As the ingot 6 continues to descend, the slits 8 contact multiple comb teeth 4. Because the downward feed thrust of the machine tool spindle is greater than the constant support force of the constant force synchronous retraction mechanism 1, the comb teeth 4 are forced to passively slide into the slits 8. Subsequently, the comb teeth 4 follow behind the tangents 7 and enter the slits 8. During this process, the comb teeth 4, through the guiding effect at their tips, discharge the high-viscosity sand that has entered the slits 8 in real time. This discharge process is carried out gently, simultaneously maintaining the open state of the slits 8 to prevent the formation of capillary adhesion. Figure 2 As shown; Step 3: Relative physical limit stage; As the ingot 6 continues to feed downwards, when the upper surface (height reference surface) of the comb tooth holder 3 is fully in contact with the bottom sacrificial pad 5, the comb tooth 4 reaches its maximum insertion depth. The comb tooth assembly 2 and the bottom sacrificial pad 5 achieve relative physical restraint. Simultaneously, since the height of the comb tooth 4 does not exceed the thickness of the bottom sacrificial pad 5, the comb tooth 4 remains embedded in the bottom sacrificial pad 5 throughout the entire process. Multiple comb tooth 4s, without contacting the upper ingot 6, form a one-to-one physical isolation barrier with the multiple cuts 8, such as... Figure 3 As shown; Step 4: Long-stroke constant force synchronous yielding stage; After achieving relative physical limitation, the spindle continues to drive the ingot 6 to perform full-stroke depth cutting. During the full-stroke depth cutting operation, the downward feed thrust forces the comb assembly 2 to remain in the maximum insertion state and simultaneously retract downwards. While the precision low-friction cylinder is continuously compressed and exhausted, a high-precision proportional pressure regulating valve is used to adjust the air supply pressure in real time, ensuring that the upward constant support force remains within the initially set constant range until the cutting operation of the ingot 6 is completed. Figure 4 As shown.

[0036] The present invention is simple to implement and has low implementation cost. It constructs a mechanical collaborative cutting scheme with bottom sacrificial pad isolation protection, passive insertion of comb toothed rack for flow guidance support, and constant force synchronous yielding. It not only effectively solves the industry pain point of adsorption and edge breakage in large-size wafer cutting, but also overcomes the technical deviation of conventional solutions in this field, and can effectively improve the cutting quality and cutting efficiency of wafers.

[0037] It should be noted that the multi-wire cutting retraction device and method provided by this invention are not only applicable to traditional free abrasive multi-wire cutting processes using high-viscosity slurry as the suspension medium (containing silicon carbide or diamond free abrasive), but also completely equivalent to bonded abrasive multi-wire cutting processes using diamond wire as the cutting tool and lubrication and cooling with water-based coolant. In bonded abrasive cutting, the bonded abrasive on the surface of the diamond wire in the cutting wire mesh directly participates in the cutting, while the water-based coolant replaces the high-viscosity slurry in the kerf. Because the water-based coolant has a high surface tension and exhibits capillary adsorption in narrow kerfs—when the kerf width reaches tens to hundreds of micrometers—the liquid film adsorption force can also cause adjacent wafers to adhere inwards and transmit lever shear stress. Therefore, the physical expansion and capillary blocking function of the comb teeth in the kerf, and the stress-free follow-up support function provided by the constant-force synchronous retraction mechanism, still play the same protective role in bonded abrasive cutting. In other words, regardless of whether the cutting medium is high-viscosity mortar or water-based coolant, the core protection logic of this invention, "using the comb assembly to block the lever shearing edge breakage caused by liquid film adsorption from the mechanical source," is fully applicable.

[0038] Furthermore, it should be noted that the multi-wire cutting retraction device and method provided by this invention are not limited to the slicing process of silicon carbide (SiC) ingots. The physical mechanism of wafer bonding and edge chipping caused by liquid film / capillary adsorption during multi-wire cutting is prevalent in large-size slicing processes of various hard and brittle materials that are susceptible to surface tension adsorption, have low bending strength, and poor fracture toughness. Therefore, this anti-adsorption edge chipping device and method can be directly extended to large-size multi-wire cutting processes of all hard and brittle material ingots or substrates that meet the above-mentioned material characteristics, including but not limited to: sapphire (Al2O3), gallium nitride (GaN), gallium arsenide (GaAs), single-crystal silicon, polycrystalline silicon, quartz glass, lithium niobate piezoelectric ceramics, diamond, and magnetic materials. The aforementioned materials also face common technical challenges in cutting and processing, such as narrow kerfs (typically tens to hundreds of micrometers), adsorption and adhesion caused by the surface tension of the cutting fluid / cooling fluid, and easy breakage of the wafer edge under leverage shear stress. The three-component linkage protection scheme provided by this invention, which consists of bottom sacrificial pad isolation protection, comb tooth physical opening to block capillary adsorption, and constant force synchronous retreat to avoid the accumulation of back-pushing internal stress, has a universal protective effect and process compatibility for the large-size wafer cutting process of the aforementioned hard and brittle materials.

[0039] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A multi-wire cutting retraction device, characterized in that, include: Bottom sacrificial pad (5), the bottom sacrificial pad (5) is bonded to the bottom end of the cutter side of the ingot (6) to be cut, and is located above the cutting wire mesh of the multi-wire cutting machine; The comb assembly (2) includes a comb base (3) and multiple comb strips (4) that are sequentially spaced along the length direction on the upper end of the comb base (3). The comb assembly (2) is horizontally positioned below the feed path of the ingot to be cut (6). At the same time, the multiple comb strips (4) are located below the multiple tangents (7) in the cutting wire mesh, and the multiple comb strips (4) are distributed in a one-to-one correspondence with the multiple tangents (7). A constant force synchronous yielding mechanism (1) is vertically arranged below the comb assembly (2). It has a telescopic support rod, and the upper end of the telescopic support rod is connected to the lower end of the comb seat (3) to provide a constant support force.

2. The multi-wire cutting retraction device according to claim 1, characterized in that, The bottom sacrificial pad (5) is bonded to the ingot to be cut (6) with high-hardness slicing adhesive.

3. The multi-wire cutting retraction device according to claim 1, characterized in that, The height of the comb bar (4) does not exceed the thickness of the bottom sacrificial pad (5), and its thickness is less than the size of the nominal cut (8).

4. The multi-wire cutting retraction device according to claim 3, characterized in that, The top of the comb bar (4) is provided with a wedge-shaped, bullet-shaped, or large arc-shaped flow guiding structure.

5. A multi-wire cutting retraction device according to claim 1, characterized in that, The comb bar (4) is made of wear-resistant polymer engineering plastic, or a composite structure of rigid metal sheet skeleton and surface flexible anti-scratch coating.

6. A multi-wire cutting retraction device according to claim 4, characterized in that, The upper surface of the comb tooth seat (3) is a planar structure and serves as a height reference surface.

7. A multi-wire cutting retraction device according to claim 6, characterized in that, The constant force synchronous retraction mechanism (1) includes a precision low friction cylinder and a high precision proportional pressure regulating valve. The telescopic support rod is the piston rod of the precision low friction cylinder. The high precision proportional regulating valve is used to establish the air circuit connection between the high pressure air source and the precision low friction cylinder, and to control the action of the high precision low friction cylinder.

8. A multi-wire cutting retraction method, employing the multi-wire cutting retraction device as described in claim 7, characterized in that, Includes the following steps: Step 1: Preset and Waiting Phase; In the initial stage of cutting, the constant force synchronous yielding mechanism (1) is activated, and the comb assembly (2) is pushed up to the preset height in the feed path using the telescopic support rod; the constant force upward of the constant force synchronous yielding mechanism (1) is set, and the comb assembly (2) is stably maintained at the preset height by the telescopic support rod, so that the comb assembly (2) is in a static waiting state. Step 2: Self-guided passive insertion phase; The ingot (6) with the bottom sacrificial pad (5) attached to it is slowly fed from top to bottom by the main shaft. Multiple tangents (7) in the cutting wire mesh cut into the bottom sacrificial pad (5) and form multiple slits (8) at the bottom of the bottom sacrificial pad (5). As the ingot (6) continues to descend, multiple comb bars (4) follow behind the multiple tangents (7) and enter the multiple slits (8). The high viscosity sand entering the slits (8) is discharged in real time through the guiding effect, and the slits (8) are kept open to block the formation of capillary adsorption force. Step 3: Relative physical limit stage; As the ingot (6) continues to feed downward, when the upper end face of the comb tooth seat (3) is fully in contact with the bottom sacrificial pad (5), the comb tooth (4) reaches the maximum insertion depth, and the comb tooth assembly (2) and the bottom sacrificial pad (5) achieve relative physical limitation. At the same time, multiple comb tooth strips (4) form a one-to-one physical isolation barrier with multiple cuts (8) without contacting the upper ingot (6). Step 4: Long-stroke constant force synchronous yielding stage; After achieving relative physical limit, the spindle continues to drive the ingot (6) to perform full-stroke depth cutting. During the full-stroke depth cutting operation, the downward feed thrust forces the comb assembly (2) to remain in the maximum insertion state and move downward synchronously. During the continuous compression and exhaust of the precision low-friction cylinder, the high-precision proportional pressure regulating valve is used to adjust the air supply pressure in real time to ensure that the upward constant support force is always maintained within the initially set constant range until the cutting operation of the ingot (6) is completed.

Images