A single crystal silicon double-side polishing slurry recycling system and method

Abstract

The application provides a single-crystal silicon double-side polishing slurry recycling system and method. The system comprises a front-end processing module, a conveying and filtering module, a recycling processing module, and a liquid supply and sand supplement module. The front-end processing module is used for receiving and distributing the slurry discharged from a double-side polishing machine table. The conveying and filtering module is used for conveying and removing impurities from the waste slurry. The recycling processing module is used for temporarily storing, homogenizing, and temperature regulating the recycled slurry to inhibit the temperature rise of the recycled slurry in the recycling and reuse process. The liquid supply and sand supplement module is used for supplying the treated recycled slurry to the double-side polishing machine table again. The application can improve the temperature stability and liquid supply stability of the recycled slurry and reduce the influence of the slurry temperature rise on the double-side polishing processing precision.

Description

Technical Field

[0001] This invention relates to the field of monocrystalline silicon processing technology, and more specifically, to a monocrystalline silicon double-sided grinding slurry recycling system and method. Background Technology

[0002] With the development of the semiconductor industry, the demand for processing monocrystalline silicon wafers continues to grow. Among these processes, double-sided grinding is typically used to remove saw marks and surface damage layers formed after wire cutting, and to improve the flatness, thickness uniformity, and surface quality of the silicon wafer. This process usually requires the continuous consumption of a special slurry composed of abrasive sand, dispersion liquid, and other components.

[0003] In current production processes, some double-sided grinding steps still employ a method of directly discharging mortar after a single use. This method not only wastes grinding sand and dispersion liquid, increasing production costs, but also creates pressure for wastewater treatment. Existing mortar recycling technologies mainly include two types: offline centralized recycling and online recycling. Offline centralized recycling typically involves collecting the discharged mortar, treating it through multiple stages, and then reusing it in production. Online recycling, on the other hand, usually involves processing the used mortar near the processing equipment and resupplying it to the machines.

[0004] However, existing mortar recycling solutions still have shortcomings in practical applications: current solutions typically focus more on filtering, iron removal, or proportioning adjustments of waste mortar, lacking effective control over the temperature during the recycling process. Mortar is prone to continuous heating during continuous grinding, pumping circulation, pipeline flow, and mixing. When the temperature-increased or fluctuating recycled mortar is resupplyed to the double-sided grinding machine, it can easily cause thermal deformation of the grinding disc, affecting the mortar viscosity, dispersion uniformity, and grinding stability, thereby leading to fluctuations in the total thickness deviation, center thickness deviation, and thickness consistency of the silicon wafers.

[0005] Therefore, it is necessary to propose a single-crystal silicon double-sided grinding slurry recycling system and method to improve the problem of insufficient temperature control in the recycling process of slurry in the existing technology, which makes it difficult to guarantee the processing stability and processing accuracy when the recycled slurry is supplied to the double-sided grinding machine again. Summary of the Invention

[0006] The purpose of this application is to provide a single-crystal silicon double-sided grinding slurry recycling system and method. By setting a temperature control unit in the online recycling process of waste slurry, the temperature state of the recycled slurry is detected, and the recycled slurry is cooled and / or its temperature is adjusted according to the detection results. This suppresses the continuous temperature rise of the slurry during the recycling process, so that the recycled slurry can be re-supplied to the double-sided grinding machine at a stable temperature. This reduces the risk of thermal deformation of the grinding disc, unstable slurry state, and fluctuations in silicon wafer thickness caused by temperature rise or fluctuation of the recycled slurry while realizing the recycling of slurry.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: In the first aspect, a single-crystal silicon double-sided grinding slurry recycling system includes a front-end processing module, a conveying and filtering module, a recycling module, and a liquid supply and sand replenishment module. The front-end processing module is used to receive the slurry discharged from the double-sided grinding machine and to import the waste slurry generated during the normal grinding process into the recycling process. The conveying and filtering module is connected to the front-end processing module and is used to convey and remove impurities from the waste mortar to obtain recycled mortar after impurity removal. The recycling module is connected to the conveying and filtering module and is used to receive the recycled mortar and temporarily store and homogenize the recycled mortar. The recycling module includes a temperature control unit, which is used to detect the temperature state of the recycled mortar and cool and / or adjust the temperature of the recycled mortar according to the detection results, so as to suppress the temperature rise of the recycled mortar during the recycling process. The liquid supply and sand replenishment module is connected to the recycling module and is used to receive the recycled slurry after temperature control and to resupply the recycled slurry to the double-sided grinding machine.

[0008] In some embodiments, the temperature control unit includes a temperature detection element, a control unit, and a temperature regulation actuator; The temperature detection device is used to detect the temperature state of the recycled mortar; The control unit is used to control the operation of the temperature regulating actuator based on the detection result of the temperature detection element; The temperature regulating actuator is used to cool and / or regulate the temperature of the recycled mortar.

[0009] In some embodiments, the temperature detection element includes a temperature control probe, and the temperature regulation actuator includes a cooling coil and a cooling water circuit assembly connected to the cooling coil.

[0010] In some embodiments, the recycling module includes a recycling sand bucket, and the cooling coil is disposed inside the recycling sand bucket and used for heat exchange between the cooling water and the recycled sand slurry inside the recycling sand bucket.

[0011] In some implementations, the control unit is configured to: When the temperature detection device detects that the temperature of the recycled mortar is higher than the preset upper limit threshold, it controls the temperature regulation actuator to start cooling. When the temperature detection device detects that the temperature of the recycled mortar is lower than the preset lower threshold, it controls the temperature regulation actuator to stop cooling or reduce the cooling intensity.

[0012] In some implementations, the preset upper limit threshold is 25°C, and the preset lower limit threshold is 22°C.

[0013] In some embodiments, the recycling module includes a recycling sand bucket and a circulating stirring unit, wherein the circulating stirring unit is used to keep the recycled mortar in the recycling sand bucket in a circulating and / or stirring state, so as to reduce the settling of the recycled mortar and improve the temperature uniformity of the recycled mortar.

[0014] In some embodiments, the front-end processing module includes a liquid-distribution unit, which is used to guide the machine rinsing fluid into a direct discharge pipeline and guide the waste slurry generated during normal grinding into a recycling pipeline according to the working mode of the double-sided grinding machine.

[0015] In some embodiments, the front-end processing module further includes a pre-filtering unit and a buffer stirring unit; The pre-filtration unit is used to remove large particulate impurities from the waste mortar. The buffer stirring unit is used to stir and buffer the pre-filtered waste mortar to reduce abrasive settling.

[0016] In some embodiments, the delivery and filtration module includes a delivery pump, a coarse filtration unit, a magnetic adsorption unit, and a fine filtration unit; The conveying pump is used to convey the waste slurry; The coarse filtration unit is used to remove medium-sized impurities from the waste mortar. The magnetic adsorption unit is used to adsorb metallic impurities in the waste mortar. The fine filtration unit is used to intercept fine impurities in the waste mortar.

[0017] In some embodiments, the coarse filtration unit, the magnetic adsorption unit, and the fine filtration unit are arranged sequentially along the mortar conveying direction; or, the magnetic adsorption unit and the fine filtration unit are integrated into the same filtration container.

[0018] In some embodiments, the magnetic adsorption unit includes a quick-release magnetic rod, and the fine filtration unit includes a quick-release fine filter screen, wherein the quick-release magnetic rod and / or the quick-release fine filter screen can be disassembled relative to the filter container for cleaning or replacement.

[0019] In some embodiments, the liquid supply and sand replenishment module includes a liquid supply mixing tank, a sand replenishment unit, and a liquid supply pump; The liquid supply mixing tank is used to receive the recycled mortar after temperature control. The sand replenishment unit is used to replenish the liquid supply mixing tank with grinding sand, dispersion liquid or new liquid; The liquid supply pump is used to resupply the recycled slurry in the liquid supply mixing tank to the double-sided grinding machine.

[0020] In some embodiments, the sand replenishment unit is used to determine whether to add grinding sand, dispersion liquid or new liquid based on at least one of the following: the recycling status of the recycled mortar, liquid level, specific gravity, concentration or grinding time change.

[0021] In some embodiments, the liquid supply pump is a peristaltic pump, which is connected to the liquid distribution plate of the double-sided grinding machine via a multi-way hose.

[0022] Secondly, a method for recycling monocrystalline silicon double-sided grinding slurry is proposed, applied to the monocrystalline silicon double-sided grinding slurry recycling system described in any of the above embodiments, the method comprising: Receive the slurry discharged from the double-sided grinding machine and introduce the waste slurry generated during normal grinding into the recycling process; The waste mortar is transported and impurities are removed to obtain recycled mortar; The recycled mortar is temporarily stored and homogenized. The temperature of the recycled mortar is detected, and the recycled mortar is cooled and / or its temperature is adjusted according to the detection results to suppress the temperature rise of the recycled mortar during the recycling process; The temperature-controlled recycled mortar is then resupplyed to the double-sided grinding machine.

[0023] In some embodiments, detecting the temperature state of the recycled mortar and cooling and / or adjusting the temperature of the recycled mortar based on the detection results includes: When the temperature of the recycled mortar is higher than the preset upper limit threshold, the cooling water inlet is activated, so that the cooling water exchanges heat with the recycled mortar through the cooling coil. When the temperature of the recycled mortar is lower than the preset lower threshold, the cooling water intake is stopped.

[0024] In some implementations, after receiving the slurry discharged from the double-sided grinding machine, it is determined whether the double-sided grinding machine is in normal grinding mode or machine washing mode. If the machine is in flushing mode, the flushing fluid is directed into the direct discharge pipeline. If in normal grinding mode, the waste mortar generated during normal grinding will be introduced into the recycling process.

[0025] In some embodiments, the conveying and impurity removal treatment of the waste mortar includes: The waste mortar is pre-filtered to remove large particulate impurities; The pre-filtered waste mortar is coarsely filtered to remove medium-sized impurities; Magnetic adsorption is applied to the coarsely filtered waste mortar to remove metallic impurities; The waste mortar after magnetic adsorption is finely filtered to remove fine impurities.

[0026] In some embodiments, before the temperature-controlled recycled mortar is resupplyed to the double-sided grinding machine, it is determined whether to add grinding sand, dispersion liquid or new liquid based on at least one of the following: the recycling status of the recycled mortar, liquid level, specific gravity, concentration or grinding time change.

[0027] Compared with the prior art, the present invention has the following beneficial effects: First, by setting up a front-end processing module, a conveying and filtering module, a recycling module, and a liquid supply and sand replenishment module, the waste mortar discharged from the double-sided grinding machine can be sequentially recycled and introduced, impurity removed, temporarily stored and homogenized, temperature controlled, and re-supplyed, thereby realizing online closed-loop recycling of waste mortar and reducing mortar consumption and waste liquid discharge.

[0028] Secondly, the present invention sets up a temperature control unit in the recycling module. By detecting the temperature state of the recycled mortar and cooling and / or adjusting the temperature of the recycled mortar according to the detection results, it can suppress the temperature rise of the recycled mortar during the recycling process, reduce the impact of the temperature fluctuation of the recycled mortar on the thermal deformation of the grinding disc, the change of mortar viscosity and the grinding stability, thereby improving the thickness consistency and processing accuracy in the double-sided grinding process.

[0029] Third, the present invention removes impurities from waste mortar through a conveying and filtering module, which reduces the risk of particulate impurities and metal impurities in the waste mortar re-entering the double-sided grinding machine with the recycled mortar, and helps to reduce scratches on the silicon wafer surface and fluctuations in grinding quality.

[0030] Fourth, the present invention uses a recycling module to temporarily store and homogenize the recycled mortar, which can reduce abrasive settling and uneven concentration distribution during the temporary storage process, so that the recycled mortar supplied to the double-sided grinding machine remains in a relatively stable state.

[0031] Fifth, the present invention resupplyes the temperature-controlled recycled mortar to the double-sided grinding machine through the liquid supply and sand replenishment module, and can replenish grinding sand, dispersion liquid or new liquid according to the recycling status, liquid level, specific gravity, concentration or grinding time of the recycled mortar, which is beneficial to maintaining the supply stability and recycling performance of the recycled mortar. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of the monocrystalline silicon double-sided grinding slurry recycling system of this application.

[0033] Figure 2 This is a schematic diagram of the process for recycling the monocrystalline silicon double-sided grinding slurry of this application.

[0034] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention.

[0035] Explanation of main component symbols Front-end processing module 10; liquid separation and diversion unit 11; pre-filtration unit 12; buffer stirring unit 13; 20. Conveying and filtering module; 21. Conveying pump; 22. Coarse filtration unit; 23. Magnetic adsorption unit; 24. Fine filtration unit; 30; 31; 32; 33; 30; 31; 32; 33; 34; Liquid supply and sand replenishment module 40; liquid supply mixing tank 41; sand replenishment unit 42; liquid supply pump 43. Detailed Implementation

[0036] Example 1: A Monocrystalline Silicon Double-Sided Grinding Slurry Recycling System In existing monocrystalline silicon double-sided grinding processes, a slurry composed of abrasive sand, dispersion, and other components is continuously supplied to the double-sided grinding machine. The abrasive particles in the slurry, under the action of the grinding disc, remove material from both sides of the silicon wafer. After grinding, the machine continuously discharges the used waste slurry. Existing slurry recycling solutions generally treat the waste slurry through methods such as collection, filtration, iron removal, specific gravity adjustment, or mixing of new and old slurry before resupplying it to the processing machine, thus achieving basic recycling of the slurry.

[0037] However, traditional mortar recycling methods, in practical applications, typically focus more on filtering, iron removal, or proportioning adjustments of waste mortar, lacking effective control over the temperature during the recycling process. Mortar is prone to continuous temperature rise during continuous grinding, pumping circulation, pipeline flow, and mixing. When the temperature-increased or fluctuating recycled mortar is resupplyed to the double-sided grinding machine, it can easily cause thermal deformation of the grinding disc, affecting the mortar viscosity, dispersion uniformity, and the interaction state of the grinding particles. This, in turn, leads to fluctuations in the total thickness deviation, center thickness deviation, and thickness consistency of the silicon wafers, impacting the processing accuracy of double-sided grinding. Simultaneously, residual impurities in the waste mortar or abrasive sedimentation during temporary storage can also affect the stability of the recycled mortar's resupply.

[0038] To address the aforementioned issues, the applicant recognized the need to develop an online mortar recycling solution suitable for the double-sided grinding process of monocrystalline silicon. While removing impurities from waste mortar, temporarily storing and homogenizing it, and resupplying it, the temperature of the recycled mortar should be monitored. Based on the monitoring results, the recycled mortar should be cooled and / or its temperature adjusted to suppress temperature rise during the mortar recycling process. This ensures that the recycled mortar maintains a suitable temperature for double-sided grinding during recycling, temporary storage, and resupply, thereby improving the stability of the recycled mortar supply and the processing accuracy of double-sided grinding.

[0039] like Figure 1 As shown, this embodiment provides a single-crystal silicon double-sided grinding slurry recycling system. This system is used to receive the slurry discharged from the double-sided grinding machine and to recycle the waste slurry generated during normal grinding process online, so that the recycled slurry can be resupplied to the double-sided grinding machine for use.

[0040] The monocrystalline silicon double-sided grinding slurry recycling system includes a front-end processing module 10, a conveying and filtering module 20, a recycling module 30, and a liquid supply and sand replenishment module 40. The front-end processing module 10 is connected to the double-sided grinding machine and receives the slurry discharged from the machine, guiding the waste slurry generated during normal grinding into the recycling process. The conveying and filtering module 20 is connected to the front-end processing module 10 and conveys and removes impurities from the waste slurry to obtain recycled slurry after impurity removal. The recycling module 30 is connected to the conveying and filtering module 20 and receives the recycled slurry, temporarily storing and homogenizing it. The liquid supply and sand replenishment module 40 is connected to the recycling module 30 and receives the temperature-controlled recycled slurry, then resupplying it to the double-sided grinding machine.

[0041] In this embodiment, the front-end processing module 10 includes a liquid-distribution unit 11, a pre-filtration unit 12, and a buffer stirring unit 13. The liquid-distribution unit 11 is used to guide the machine rinsing fluid into the direct discharge pipeline and guide the waste slurry generated during normal grinding into the recycling pipeline according to the working mode of the double-sided grinding machine. This avoids diluting or contaminating the recycled slurry after the machine rinsing fluid enters the recycling process.

[0042] The pre-filtration unit 12 is used to remove large particulate impurities from the waste mortar. In one specific embodiment, the pre-filtration unit 12 can be a wire mesh filter. After passing through the pre-filtration unit 12, large particulate impurities such as broken silicon flakes and hard lumps are intercepted. The buffering and stirring unit 13 is used to receive the pre-filtered waste mortar and to stir and buffer it to reduce abrasive settling, ensuring the waste mortar remains in a relatively uniform suspended state before entering the conveying and filtering module 20. The buffering and stirring unit 13 may include a small stirring and buffer tank and a stirring impeller disposed within the small stirring and buffer tank.

[0043] The conveying and filtering module 20 includes a conveying pump 21, a coarse filtration unit 22, a magnetic adsorption unit 23, and a fine filtration unit 24. The conveying pump 21 draws waste mortar from the buffer mixing unit 13 and conveys it to the subsequent filtering unit. The coarse filtration unit 22 removes medium-sized impurities from the waste mortar. The magnetic adsorption unit 23 adsorbs metallic impurities from the waste mortar. The fine filtration unit 24 intercepts fine impurities from the waste mortar.

[0044] In some embodiments, the coarse filtration unit 22, the magnetic adsorption unit 23, and the fine filtration unit 24 are arranged sequentially along the mortar conveying direction. In other embodiments, the magnetic adsorption unit 23 and the fine filtration unit 24 may be integrated within the same filter container. The magnetic adsorption unit 23 may include a quick-release magnetic rod, and the fine filtration unit 24 may include a quick-release fine filter screen. The quick-release magnetic rod and / or the quick-release fine filter screen can be removed relative to the filter container for cleaning or replacement.

[0045] The recycling module 30 includes a recycling sand tank 31, a circulating stirring unit 32, and a temperature control unit 33. The recycling sand tank 31 is used to temporarily store the recycled mortar after impurity removal treatment. The circulating stirring unit 32 is used to keep the recycled mortar in the recycling sand tank 31 in a circulating and / or stirring state, so as to reduce the settling of the recycled mortar and improve the concentration uniformity and temperature uniformity of the recycled mortar.

[0046] The temperature control unit 33 is used to detect the temperature status of the recycled mortar and, based on the detection results, cool and / or adjust the temperature of the recycled mortar to suppress the temperature rise of the recycled mortar during the recycling process. Since double-sided grinding is a continuous processing step, the mortar is subject to factors such as grinding friction, pump circulation, pipeline flow, stirring shear, and continuous operation during recycling, continuously generating or absorbing heat. If the temperature of the recycled mortar continues to rise or fluctuates significantly, when the recycled mortar is resupplyed to the double-sided grinding machine, it can easily lead to thermal deformation of the grinding disc, affecting the mortar viscosity, dispersion uniformity, and the action state of the grinding particles, thereby affecting the total thickness deviation, center thickness deviation, and thickness consistency of the silicon wafer. Therefore, this embodiment uses the temperature control unit 33 to regulate the temperature of the recycled mortar, maintaining it within a suitable temperature range for double-sided grinding resupply during recycling, temporary storage, and resupply.

[0047] Specifically, the temperature control unit 33 includes a temperature detection element, a control unit, and a temperature regulation actuator. The temperature detection element detects the temperature state of the recycled mortar and outputs a temperature detection signal to the control unit. The control unit controls the operation of the temperature regulation actuator based on the detection result of the temperature detection element. The temperature regulation actuator is used to cool and / or regulate the temperature of the recycled mortar.

[0048] In one specific embodiment, the temperature detection element includes a temperature control probe, and the temperature regulation actuator includes a cooling coil and a cooling water circuit assembly connected to the cooling coil. The cooling coil is disposed within the sand recovery tank 31 and is used for heat exchange between the cooling water and the recovered mortar within the sand recovery tank 31. The cooling water circuit assembly may include a cooling water inlet pipe, a cooling water outlet pipe, and a solenoid valve disposed on the cooling water inlet pipe. The control unit is electrically or signal-connected to the temperature control probe and the solenoid valve to control the flow of cooling water based on the temperature of the recovered mortar collected by the temperature control probe.

[0049] During system operation, the temperature control probe monitors the temperature of the recycled mortar in real time or periodically and sends the results to the control unit. When the control unit determines that the temperature of the recycled mortar is higher than a preset upper threshold, it controls the temperature regulation actuator to start cooling; when the control unit determines that the temperature of the recycled mortar is lower than a preset lower threshold, it controls the temperature regulation actuator to stop cooling or reduce the cooling intensity. As a specific implementation, the preset upper threshold can be 25°C, and the preset lower threshold can be 22°C. When the temperature of the recycled mortar is higher than 25°C, the cooling water circuit assembly opens, allowing cooling water to enter the cooling coil and exchange heat with the recycled mortar; when the temperature of the recycled mortar is lower than 22°C, the cooling water circuit assembly stops the cooling water intake. The above temperature thresholds are only one example; in other implementations, other temperature thresholds or temperature ranges can be set according to the double-sided grinding process requirements, mortar formulation, machine operating status, or ambient temperature.

[0050] The liquid supply and sand replenishment module 40 includes a liquid supply mixing tank 41, a sand replenishment unit 42, and a liquid supply pump 43. The liquid supply mixing tank 41 receives the temperature-controlled recycled mortar and temporarily stores and mixes it. The sand replenishment unit 42 replenishes the liquid supply mixing tank 41 with grinding sand, dispersion liquid, or new liquid. The liquid supply pump 43 resupply the recycled mortar in the liquid supply mixing tank 41 to the double-sided grinding machine.

[0051] In some embodiments, the sand replenishment unit 42 is used to determine whether to add grinding sand, dispersion liquid, or new liquid based on at least one of the following: the recycling status of the recycled mortar, liquid level, specific gravity, concentration, or grinding time changes. For example, when the recycled mortar has been recycled to a preset number of cycles, if the grinding time increases by a preset proportion compared to the normal grinding time, and the specific gravity or concentration of the recycled mortar deviates from the target range, grinding sand and dispersion liquid can be added to the liquid supply mixing tank 41, and after stirring evenly, it can be detected whether the specific gravity or concentration of the recycled mortar has returned to the target range. The above sand replenishment method is only an example. In other embodiments, manual sand replenishment, automatic metering sand replenishment, or sand replenishment based on other process parameters can also be used.

[0052] In one specific embodiment, the liquid supply pump 43 is a peristaltic pump, which is connected to the distribution plate of the double-sided grinding machine through a multi-way hose. The recycled mortar, after being temporarily stored and stirred in the liquid supply mixing tank 41, is transported by the peristaltic pump to the distribution plate of the double-sided grinding machine, and then distributed by the distribution plate to the double-sided grinding processing area.

[0053] Example 2: A method for recycling monocrystalline silicon double-sided grinding slurry like Figure 2 As shown, this embodiment also provides a method for recycling monocrystalline silicon double-sided grinding slurry, which can be applied to the above-mentioned monocrystalline silicon double-sided grinding slurry recycling system. The method includes the following steps: S1: The double-sided grinding machine discharges mortar.

[0054] The double-sided grinding machine discharges slurry during processing. The slurry may include waste slurry generated during normal grinding, or machine rinsing fluid generated during machine washing.

[0055] S2: Determine the machine's operating mode.

[0056] The liquid separation and diversion unit 11 determines whether the double-sided grinding machine is in normal grinding mode or machine flushing mode. If it is in machine flushing mode, the machine flushing fluid is introduced into the direct discharge pipeline so that the machine flushing fluid is discharged directly; if it is in normal grinding mode, the waste mortar generated during normal grinding is introduced into the recycling process.

[0057] S3: Pre-filter the waste mortar.

[0058] After the waste slurry generated during normal grinding enters the recycling process, it first passes through the pre-filtration unit 12 to remove large particulate impurities in the waste slurry, such as broken silicon wafers and hard lumps.

[0059] S4: Buffer and stir the pre-filtered waste mortar.

[0060] The pre-filtered waste mortar enters the buffer mixing unit 13, where the abrasive settling is reduced by mixing and buffering, so that the waste mortar remains in a relatively uniform suspended state.

[0061] S5: Transporting and removing impurities from waste mortar.

[0062] The conveying pump 21 draws waste mortar from the buffer mixing unit 13 and conveys it to the conveying and filtering module 20. In the conveying and filtering module 20, the waste mortar undergoes coarse filtration, magnetic adsorption, and fine filtration to remove medium-sized impurities, metallic impurities, and fine impurities, respectively, to obtain recycled mortar after impurity removal treatment.

[0063] S6: Temporarily store and homogenize the recycled mortar and control its temperature.

[0064] After impurity removal, the recycled mortar enters the recycled sand tank 31. The circulating stirring unit 32 keeps the recycled mortar in the recycled sand tank 31 in a state of circulation and / or stirring to reduce settling and improve uniformity. At the same time, the temperature control unit 33 detects the temperature of the recycled mortar and cools and / or adjusts the temperature of the recycled mortar according to the detection results to suppress the temperature rise of the recycled mortar during the recycling process and keep the recycled mortar within a preset temperature range suitable for double-sided grinding and resupply.

[0065] In one specific implementation, when the temperature of the recycled mortar is higher than a preset upper limit threshold, the control unit starts the cooling water intake, so that the cooling water exchanges heat with the recycled mortar through the cooling coil; when the temperature of the recycled mortar is lower than a preset lower limit threshold, the control unit stops the cooling water intake.

[0066] S7: Determine whether additional grinding sand and / or dispersion is needed.

[0067] The temperature-controlled recycled mortar enters the liquid supply and sand replenishment module 40. The sand replenishment unit 42 determines whether grinding sand, dispersion liquid, or new liquid needs to be added based on at least one of the following: the recycling status of the recycled mortar, liquid level, specific gravity, concentration, or grinding time changes. If it is determined that replenishment is needed, grinding sand, dispersion liquid, or new liquid is added to the liquid supply mixing tank 41 and stirred; if it is determined that replenishment is not needed, the liquid supply step begins.

[0068] S8: Recycle mortar and feed it back to the double-sided grinding machine.

[0069] The liquid supply pump 43 resupply the recycled slurry in the liquid supply mixing tank 41 to the double-sided grinding machine. In one specific embodiment, the liquid supply pump 43 is a peristaltic pump, which delivers the recycled slurry to the distribution plate of the double-sided grinding machine through multiple hoses. The distribution plate then distributes the recycled slurry to the double-sided grinding processing area. After the liquid supply is completed, the double-sided grinding machine continues to discharge slurry and returns to S1, forming an online closed-loop cycle.

[0070] Through the aforementioned system and method, the waste slurry discharged from the double-sided grinding machine can sequentially undergo pattern diversion, pre-filtration, buffer stirring, impurity removal, temporary storage and homogenization, temperature control, sand replenishment judgment, and re-supply treatment. In particular, by using the temperature control unit 33 to detect the temperature state of the recycled slurry and cooling and / or adjusting the temperature of the recycled slurry based on the detection results, the temperature rise of the recycled slurry during the recycling process can be suppressed, reducing the impact of temperature fluctuations of the recycled slurry on the thermal deformation of the grinding disc, the stability of the slurry state, and the uniformity of silicon wafer thickness, thereby improving the processing stability when the recycled slurry is re-supplyed to the double-sided grinding machine.

[0071] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A single-crystal silicon double-sided grinding slurry recycling system, characterized in that, It includes a front-end processing module, a conveying and filtering module, a recycling module, and a liquid supply and sand replenishment module; The front-end processing module is used to receive the slurry discharged from the double-sided grinding machine and to import the waste slurry generated during the normal grinding process into the recycling process. The conveying and filtering module is connected to the front-end processing module and is used to convey and remove impurities from the waste mortar to obtain recycled mortar after impurity removal. The recycling module is connected to the conveying and filtering module and is used to receive the recycled mortar and temporarily store and homogenize the recycled mortar. The recycling module includes a temperature control unit, which is used to detect the temperature state of the recycled mortar and cool and / or adjust the temperature of the recycled mortar according to the detection results, so as to suppress the temperature rise of the recycled mortar during the recycling process. The liquid supply and sand replenishment module is connected to the recycling module and is used to receive the recycled slurry after temperature control and to resupply the recycled slurry to the double-sided grinding machine.

2. The monocrystalline silicon double-sided grinding slurry recycling system according to claim 1, characterized in that, The temperature control unit includes a temperature detection element, a control unit, and a temperature regulation actuator; The temperature detection device is used to detect the temperature state of the recycled mortar; The control unit is used to control the operation of the temperature regulating actuator based on the detection result of the temperature detection element; The temperature regulating actuator is used to cool and / or regulate the temperature of the recycled mortar.

3. The monocrystalline silicon double-sided grinding slurry recycling system according to claim 2, characterized in that, The temperature detection device includes a temperature control probe, and the temperature regulation actuator includes a cooling coil and a cooling water circuit assembly connected to the cooling coil.

4. The monocrystalline silicon double-sided grinding slurry recycling system according to claim 3, characterized in that, The recycling module includes a recycling sand bucket, and the cooling coil is disposed inside the recycling sand bucket and is used to exchange heat with the recycled mortar in the recycling sand bucket through cooling water.

5. The monocrystalline silicon double-sided grinding slurry recycling system according to claim 2, characterized in that, The control unit is configured to: When the temperature detection device detects that the temperature of the recycled mortar is higher than the preset upper limit threshold, it controls the temperature regulation actuator to start cooling. When the temperature detection device detects that the temperature of the recycled mortar is lower than the preset lower threshold, it controls the temperature regulation actuator to stop cooling or reduce the cooling intensity.

6. The monocrystalline silicon double-sided grinding slurry recycling system according to claim 1, characterized in that, The recycling module includes a recycling sand bucket and a circulating stirring unit. The circulating stirring unit is used to keep the recycled mortar in the recycling sand bucket in a circulating and / or stirring state, so as to reduce the settling of the recycled mortar and improve the temperature uniformity of the recycled mortar.

7. The monocrystalline silicon double-sided grinding slurry recycling system according to claim 1, characterized in that, The front-end processing module includes a liquid separation and diversion unit, which is used to guide the machine rinsing fluid into the direct discharge pipeline according to the working mode of the double-sided grinding machine, and to guide the waste slurry generated during normal grinding into the recycling pipeline.

8. The monocrystalline silicon double-sided grinding slurry recycling system according to claim 1, characterized in that, The front-end processing module also includes a pre-filtering unit and a buffer stirring unit; The pre-filtration unit is used to remove large particulate impurities from the waste mortar. The buffer stirring unit is used to stir and buffer the pre-filtered waste mortar to reduce abrasive settling.

9. The single-crystal silicon double-sided grinding slurry recycling system according to claim 1, characterized in that, The delivery and filtration module includes a delivery pump, a coarse filtration unit, a magnetic adsorption unit, and a fine filtration unit; The conveying pump is used to convey the waste slurry; The coarse filtration unit is used to remove medium-sized impurities from the waste mortar. The magnetic adsorption unit is used to adsorb metallic impurities in the waste mortar. The fine filtration unit is used to intercept fine impurities in the waste mortar.

10. A method for recycling monocrystalline silicon double-sided grinding slurry, characterized in that, The method applied to the monocrystalline silicon double-sided grinding slurry recycling system according to any one of claims 1 to 9 includes: Receive the slurry discharged from the double-sided grinding machine and introduce the waste slurry generated during normal grinding into the recycling process; The waste mortar is transported and impurities are removed to obtain recycled mortar; The recycled mortar is temporarily stored and homogenized. The temperature of the recycled mortar is detected, and the recycled mortar is cooled and / or its temperature is adjusted according to the detection results to suppress the temperature rise of the recycled mortar during the recycling process; The temperature-controlled recycled mortar is then resupplyed to the double-sided grinding machine.

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