Wafer slicing method and slicing system

Abstract

The invention discloses a wafer slicing method and a wafer slicing system, and the wafer slicing method comprises the steps: in the slicing process, standard cutting fluid is adopted as cutting fluid in a cutting stage, and finished product cutting fluid mixed with recovery fluid is adopted as cutting fluid in other stages except the cutting stage. Standard cutting fluid is adopted in the cutting stage, and the standard cutting fluid does not contain granular impurities, so that silicon powder and silicon sludge on the cutting face can be better washed away, the risk of poor cutting due to the fact that the cutting fluid is polluted by impurity particles is avoided, the cleanliness of the surface of the wafer can be improved, the stability of the cutting process can be guaranteed, and the service life of the wafer is prolonged. The TTV / WARP cutting yield of the wafer is improved; and the finished product cutting liquid mixed with the recovery liquid is used in other slicing steps except for knife feeding, so that the cutting stock solution cost can be saved, and the wafer slicing cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic product preparation, and in particular to a wafer slicing method and a slicing system. Background Art

[0002] Wafers are obtained by slicing crystal rods. When slicing the crystal rods, cutting fluid will be sprayed on them to achieve the purpose of cooling and washing the silicon powder produced by slicing. Different cutting fluids will have different effects on the stability and surface cleanliness of wafer slices. The best effect is to use standard cutting fluid for all cutting fluids. Standard cutting fluid is a cutting fluid made of pure water and cutting stock fluid in a certain proportion. However, it is too expensive to use standard cutting fluid all the time, which makes the slicing cost high.

[0003] As the cost requirements for semiconductor wafer manufacturing are increasing, and large-size wafers have advantages in terms of the number of chips produced per unit and unit cost, the size of semiconductor silicon substrates has also tended to be larger in diameter, from the earliest 2 inches and 3 inches to today's 8 inches, 12 inches, and 18 inches. The larger the wafer size, the higher the stability and cleanliness requirements during slicing, and the higher the slicing cost, so a method is needed that can not only ensure the stability during slicing and the cleanliness of the wafer surface, but also reduce the slicing cost. Summary of the invention

[0004] The object of the present invention is to overcome the above-mentioned shortcomings and provide a wafer slicing method and a slicing system, which can ensure the stability of the cutting process, improve the wafer TTV / WARP cutting yield, and reduce the slicing cost.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is:

[0006] A wafer slicing method comprises: in the slicing process, the cutting fluid in the knife-entering stage adopts standard cutting fluid, and the cutting fluid in other stages other than the knife-entering stage adopts finished cutting fluid mixed with recycled fluid.

[0007] The standard cutting fluid is prepared by mixing and stirring pure water and cutting stock fluid, and the finished cutting fluid is prepared by mixing and stirring the recovered fluid, pure water and cutting stock fluid.

[0008] The preparation method of the standard cutting fluid is: pure water and cutting stock solution are mixed and stirred in a fixed ratio, and then the mixed liquid is tested to see if it meets the standard for use of the standard cutting fluid. If it does, it means that the mixed liquid can be used as the standard cutting fluid; if it does not meet the standard, pure water or cutting stock solution is injected according to the test results, and real-time testing is performed during the injection process until it meets the standard.

[0009] Initially, when pure water and cutting fluid are mixed in a fixed ratio, when the total amount of pure water and cutting fluid reaches the first set amount, stop adding water and cutting fluid, and then test whether the mixed liquid meets the standard for use of standard cutting fluid. When the test meets the standard, stop adding water and cutting fluid.

[0010] During the slicing process, when the standard cutting fluid is less than the second set amount, pure water and cutting fluid are added to the standard cutting fluid in a fixed ratio and mixed and stirred. When the total amount of liquid reaches the first set value, the addition of water and cutting fluid is stopped again, and then the mixed liquid is tested to see if it meets the usage standards of the standard cutting fluid.

[0011] By testing whether the concentration of a certain active ingredient in the mixed liquid reaches the set standard, it is detected whether the mixed liquid meets the use standard of the standard cutting fluid.

[0012] During the slicing process, the waste liquid generated by slicing is recovered and treated, and the turbidity of the treated waste liquid is tested. If the turbidity meets the standard, it can be used as the recovered liquid; if it does not meet the standard, it is treated again until its turbidity meets the standard.

[0013] The recovered liquid, pure water and cutting liquid are injected into the finished liquid preparation container in a fixed ratio. When the total amount of the mixed liquid in the finished liquid preparation container reaches the third set amount, the injection is suspended to detect whether the mixed liquid meets the use standard of the finished cutting liquid. If it does not meet the standard, pure water or cutting liquid is injected again according to the test results. Real-time detection is performed during the injection process until the mixed liquid meets the use standard of the finished cutting liquid.

[0014] The mixed liquid in the finished liquid preparation container that has passed the inspection is injected into the finished liquid container, and the liquid in the finished liquid container is kept in a stirred state. The liquid in the finished liquid container is the finished cutting liquid mixed with the recovery liquid. Preferably, whether the mixed liquid meets the use standard of the finished cutting liquid is detected by detecting whether the concentration of a certain active ingredient in the mixed liquid in the finished liquid preparation container reaches the set standard.

[0015] When the total amount of liquid in the finished liquid preparation container is less than the fourth set amount, the injection into the finished liquid container is stopped; then pure water, cutting raw liquid and the recovered liquid that has met the test standards are injected into the finished liquid preparation container in a fixed ratio until the total amount of liquid reaches the third set amount again, then the injection is stopped to check whether the mixed liquid meets the use standards of the finished cutting liquid, and the above cycle is repeated.

[0016] During the stirring process of the standard cutting fluid and the finished cutting fluid, the temperature of the liquid is detected in real time. When the temperature exceeds the maximum value of the set temperature, the liquid is cooled so that the temperature of the liquid is within the set temperature range.

[0017] A wafer slicing system, comprising:

[0018] Standard cutting fluid supply device, can provide standard cutting fluid;

[0019] Finished cutting fluid supply device, which can provide finished cutting fluid mixed with recycled fluid;

[0020] A dynamic control group connected to the standard cutting fluid supply device and the finished cutting fluid supply device;

[0021] According to the control of the dynamic regulation group, in the slicing entry stage, the standard cutting liquid supply device provides standard cutting liquid, and in other slicing stages other than the slicing entry stage, the finished cutting liquid supply device switches to provide finished cutting liquid mixed with recovery liquid.

[0022] The wafer slicing system also includes a pure water supply device connected to the standard cutting liquid supply device and the finished cutting liquid supply device, a cutting stock liquid supply device, and an online waste liquid recovery and treatment device connected to the finished cutting liquid supply device. The online waste liquid recovery and treatment device is configured to be able to online recover and treat the waste liquid generated during the slicing process to obtain the recovered liquid; the standard cutting liquid supply device receives the pure water supplied by the pure water supply device and the cutting stock liquid supplied by the cutting stock liquid supply device, and mixes them into the qualified standard cutting liquid; the standard cutting liquid supply device receives the pure water supplied by the pure water supply device, the cutting stock liquid supplied by the cutting stock liquid supply device, and the recovered liquid provided by the online waste liquid recovery and treatment device, and mixes them into the qualified finished cutting liquid mixed with the recovered liquid.

[0023] The wafer slicing system also includes a turbidity detection device, which performs turbidity detection on the waste liquid recovered and processed by the online waste liquid recovery and processing device.

[0024] The standard cutting fluid supply device comprises:

[0025] A standard cutting liquid preparation device, comprising a standard liquid preparation container and a stirring device arranged in the standard liquid preparation container, wherein the pure water in the pure water supply device and the cutting stock liquid in the cutting stock liquid supply device can be injected into the standard liquid preparation container, and the stirring device stirs the liquid in the standard liquid preparation container;

[0026] The standard cutting fluid detection device is used to detect whether the liquid in the standard liquid preparation container meets the use standard of the standard cutting fluid.

[0027] A first liquid level line and a second liquid level line are provided in the standard liquid preparation container. When the liquid reaches the first liquid level line, it indicates that the total amount of liquid in the standard liquid preparation container has reached the first set amount; when the liquid reaches the second liquid level line, it indicates that the total amount of liquid in the standard liquid preparation container has reached the second set amount; a liquid level sensor is also provided in the standard liquid preparation container, and the liquid level sensor is configured to detect the liquid level of the liquid in the standard liquid preparation container.

[0028] The standard cutting liquid supply device also includes a temperature control component connected to the standard liquid preparation container, and the temperature control component includes a temperature sensor for monitoring the temperature of the liquid in the standard liquid preparation container and a cooling device for cooling the liquid.

[0029] The finished cutting fluid supply device comprises:

[0030] A finished liquid preparation container, into which the pure water in the pure water supply device and the cutting liquid and the recovery liquid in the cutting liquid supply device are injected;

[0031] Finished product cutting fluid detection device, used to detect whether the mixed liquid in the finished product liquid preparation container meets the use standard of the finished product cutting fluid;

[0032] The finished liquid container is used to receive the mixed liquid in the finished liquid preparation container that has been tested and found to be up to standard by the finished cutting liquid testing device, and the finished liquid container is provided with a stirring device, and the stirring device stirs the liquid in the finished liquid container. The liquid in the finished liquid container is the finished cutting liquid mixed with the recovered liquid.

[0033] A third liquid level line and a fourth liquid level line are provided in the finished liquid preparation container. When the liquid in the finished liquid preparation container reaches the third liquid level line, it indicates that the total amount of liquid in the finished liquid preparation container has reached the third set amount; when the liquid reaches the fourth liquid level line, it indicates that the total amount of liquid in the finished liquid preparation container has reached the fourth set amount; a liquid level sensor is also provided in the finished liquid preparation container, and the liquid level sensor is configured to detect the liquid level of the liquid in the finished liquid preparation container.

[0034] The quasi-cutting liquid detection device and the finished cutting liquid detection device are both configured as component detection devices;

[0035] The finished cutting liquid supply device also includes a temperature control component connected to the finished liquid container, and the temperature control component includes a temperature sensor for monitoring the temperature of the liquid in the finished liquid container and a cooling device for cooling the liquid.

[0036] Because the present invention adopts the above technical solution, it has the following beneficial effects:

[0037] 1. When slicing, standard cutting fluid is used in the knife entry stage, because the standard cutting fluid does not contain granular impurities, which can better wash away the silicon powder and silicon mud on the cutting surface, avoiding the risk of impurity particles contaminating the cutting fluid and causing poor knife entry, thereby not only improving the cleanliness of the wafer surface, but also ensuring the stability of the cutting process and improving the wafer TTV / WARP cutting yield;

[0038] 2. In the slicing stages other than the knife insertion, the finished cutting fluid mixed with the recycled liquid is used, which can save the cost of the cutting liquid and thus reduce the wafer slicing cost; and the finished cutting fluid is not only the recycled waste liquid, but also a mixture of pure water and cutting liquid, which can also ensure the overall stability of the finished cutting fluid, ensure the process stability of other slicing stages other than the knife insertion, and further ensure the overall surface cleanliness of the wafer and the TTV / WARP cutting yield;

[0039] 3. Whether it is standard cutting fluid or finished cutting fluid, when mixing, the corresponding liquid is first added in a fixed ratio. After the component test fails to meet the standard, pure water and cutting fluid are dynamically injected according to the test results. This combination makes the mixing of standard cutting fluid that meets the standard (that is, can be put into use) and finished cutting fluid easier to control;

[0040] 4. During the slicing process, both the standard cutting fluid and the finished cutting fluid can be mixed online, and can be mixed in real time according to the usage of each cutting fluid, which not only reduces the complexity of the transportation of each cutting fluid, but also ensures the normal supply of the standard cutting fluid and the finished cutting fluid, thereby ensuring the normal slicing;

[0041] 5. Online recovery of waste liquid generated during the slicing process and processing it into reusable recycled liquid can prevent waste liquid from accumulating in the slicer, thereby improving the cleanliness of the slicer. This can further improve the stability of the slicing process, thereby improving the cleanliness of the wafer surface and the slicing quality, that is, improving the wafer TTV / WARP cutting yield;

[0042] 6. Using the dynamic control group to switch between different cutting fluids can reduce the labor intensity of personnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 The wafer is obtained by cutting by conventional method;

[0044] Figure 2 It is a working schematic diagram of the wafer slicing system of the present invention;

[0045] Figure 3 The wafer is obtained by cutting using the method of the present invention;

[0046] Figure 4The TTV comparison diagrams of wafers cut by the conventional method and the method of the present invention are shown respectively;

[0047] Figure 5 The figure is a comparison chart of the Warp values ​​of wafers cut by the conventional method and the method of the present invention. DETAILED DESCRIPTION

[0048] The invention discloses a wafer slicing method. During the slicing process, a cutting fluid in a knife-entering stage adopts a standard cutting fluid, and a cutting fluid in other stages other than the knife-entering stage adopts a finished cutting fluid mixed with a recycling fluid.

[0049] The standard cutting fluid is prepared by mixing and stirring pure water and cutting stock fluid.

[0050] The preparation method of the standard cutting fluid is: pure water and cutting stock solution are mixed and stirred in a fixed ratio, and then the mixed liquid is tested to see if it meets the standard for use of the standard cutting fluid. If it does, it means that the mixed liquid can be used as the standard cutting fluid; if it does not meet the standard, pure water or cutting stock solution is injected according to the test results, and real-time testing is performed during the injection process until it meets the standard.

[0051] In this embodiment, whether the mixed liquid meets the use standard of the standard cutting fluid is detected by detecting whether the concentration of a certain effective component in the mixed liquid reaches the set standard.

[0052] Furthermore, in the initial state, that is, before slicing begins and before standard cutting fluid is used, when pure water and cutting fluid are mixed in a fixed ratio, when the total amount of liquid (that is, the total amount of pure water and cutting fluid) reaches the first set amount, the addition of water and cutting fluid is stopped, and then the mixed liquid is tested to see whether it meets the standard for use of the standard cutting fluid, that is, whether the concentration of a certain active ingredient in the mixed liquid meets the standard. When the concentration of the active ingredient in the mixed liquid meets the standard, the addition of water and cutting stock fluid is stopped.

[0053] During the slicing process, when the standard cutting liquid is less than the second set amount, pure water and cutting stock liquid are added to the standard cutting liquid in a fixed ratio and mixed and stirred. When the total amount of the liquid reaches the first set value, the addition of water and cutting liquid is stopped again, and then the mixed liquid is tested to see if it meets the standard for use of the standard cutting liquid, that is, to see if the concentration of a certain active ingredient in the mixed liquid meets the standard. If it does not meet the standard, pure water or cutting stock liquid is injected again according to the test results. During the injection process, it is tested in real time whether the mixed liquid meets the standard for use of the standard cutting liquid until it meets the standard, that is, until the concentration of a certain active ingredient in the mixed liquid meets the standard. In this way, it can be ensured that the standard cutting liquid can be provided from the beginning of slicing to the end of slicing, so as to avoid the interruption of the standard cutting liquid and affect the slicing.

[0054] Similarly, when the concentration of the active ingredient in the mixed liquid reaches the standard, stop adding water and cutting stock solution until the total amount is less than the second set amount, then add pure water and cutting stock solution to the standard cutting liquid in a fixed ratio and mix and stir, and repeat this cycle. In this way, the standard cutting liquid is allocated in real time according to the usage amount, which not only reduces the complexity of handling the standard cutting liquid, but also ensures the normal supply of the standard cutting liquid, thereby ensuring the normal slicing.

[0055] The finished cutting fluid is prepared by mixing and stirring the recovered fluid, pure water and the original cutting fluid.

[0056] During the slicing process, the waste liquid generated by slicing is recovered and treated, and the turbidity of the treated waste liquid is tested. If the turbidity meets the standard, it can be used as the recovered liquid; if it does not meet the standard, it is treated again until its turbidity meets the standard.

[0057] The recovery and treatment of the waste liquid can be carried out by any known and feasible technical method, and is not the inventive point of the present invention, so it will not be described here in detail.

[0058] The preparation method of the finished cutting fluid mixed with the recovery fluid is as follows:

[0059] Inject the recovered liquid, pure water and cutting stock liquid into the finished liquid preparation container according to a fixed ratio. When the total amount of the mixed liquid in the finished liquid preparation container reaches a third set amount, suspend injection to detect whether the mixed liquid meets the use standard of the finished cutting liquid. If it does not meet the standard, inject pure water or cutting stock liquid according to the test result, and perform real-time detection during the injection process until the mixed liquid meets the use standard of the finished cutting liquid;

[0060] Then, the mixed liquid in the finished liquid preparation container that has passed the above-mentioned inspection is injected into the finished liquid container, and the liquid in the finished liquid container is kept in a stirred state. The liquid in the finished liquid container is the finished cutting liquid mixed with the recovery liquid.

[0061] Preferably, the qualified mixed liquid in the finished liquid preparation container is continuously injected into the finished liquid container. When the total amount of liquid in the finished liquid preparation container is less than the fourth set amount, the injection into the finished liquid container is suspended. Then, pure water, cutting liquid and the recovered liquid that has passed the above-mentioned inspection are injected into the finished liquid preparation container in a fixed ratio until the total amount of liquid reaches the third set amount again. The injection is suspended to detect whether the mixed liquid meets the use standard of the finished cutting liquid. If it does not meet the standard, pure water or cutting liquid is injected again according to the test results. Real-time detection is performed during the injection process until the mixed liquid meets the use standard of the finished cutting liquid.

[0062] The above reciprocating cycle is carried out. In this way, the finished cutting liquid is adjusted in real time according to the usage of the finished cutting liquid, which can ensure that there is always a safe set amount of finished cutting liquid in the finished liquid container (the liquid level is higher than the second set liquid level line), that is, the normal supply of the finished cutting liquid is guaranteed to avoid the finished cutting liquid from being interrupted and affecting the slicing.

[0063] Similarly, whether the mixed liquid meets the use standard of the finished cutting fluid is also detected by detecting whether the concentration of a certain active ingredient in the mixed liquid in the finished liquid preparation container reaches the set standard.

[0064] Regardless of whether it is the standard cutting fluid or the finished cutting fluid, when preparing it, the corresponding liquid is first added in a fixed ratio. After the component detection does not meet the standard, pure water and cutting liquid are dynamically injected according to the test results. This combination of methods can make the preparation of standard cutting fluid that meets the standard (i.e. can be put into use) and finished cutting fluid easier to control.

[0065] Furthermore, during the stirring process of the standard cutting fluid and the finished cutting fluid, the temperature of the liquid is detected in real time. When the temperature exceeds the maximum value of the set temperature, the liquid is cooled so that the temperature of the liquid is within the set temperature range. Because the stability of the cutting fluid temperature affects the performance parameters of the wafer, the cutting fluid needs to be kept within a certain temperature range. Too high or too low will have a bad effect on the performance of the wafer; and if there is no other operation, the stirring action will cause the liquid temperature to rise.

[0066] In this embodiment, the set temperature of the liquid is 15-25° C. That is, when it is detected that the liquid temperature exceeds 25° C., the liquid needs to be cooled.

[0067] The present invention also discloses a wafer slicing system, which comprises:

[0068] Standard cutting fluid supply device, can provide standard cutting fluid;

[0069] Finished cutting fluid supply device, which can provide finished cutting fluid mixed with recycled fluid;

[0070] A dynamic control group connected to the standard cutting fluid supply device and the finished cutting fluid supply device;

[0071] According to the control of the dynamic regulation group, in the slicing entry stage, the standard cutting liquid supply device provides standard cutting liquid, and in other slicing stages other than the slicing entry stage, the finished cutting liquid supply device switches to provide finished cutting liquid mixed with recovery liquid.

[0072] The wafer slicing system also includes a pure water supply device connected to the standard cutting liquid supply device and the finished cutting liquid supply device, a cutting stock liquid supply device, and an online waste liquid recovery and treatment device connected to the finished cutting liquid supply device. The online waste liquid recovery and treatment device is configured to be able to online recover and treat the waste liquid generated during the slicing process to obtain the recovered liquid; the standard cutting liquid supply device receives the pure water supplied by the pure water supply device and the cutting stock liquid supplied by the cutting stock liquid supply device, and mixes them into the standard cutting liquid; the standard cutting liquid supply device receives the pure water supplied by the pure water supply device, the cutting stock liquid supplied by the cutting stock liquid supply device, and the recovered liquid provided by the online waste liquid recovery and treatment device, and mixes them into the finished cutting liquid mixed with the recovered liquid.

[0073] Preferably, the wafer slicing system also includes a turbidity detection device, which performs turbidity detection on the waste liquid recovered and treated by the online waste liquid recovery and treatment device. If the turbidity detection meets the standard, the waste liquid can be used as the recovered liquid; if it does not meet the standard, it will be processed again until its turbidity meets the standard.

[0074] The pure water supply device and the cutting liquid supply device can be any known and feasible container storing corresponding liquids, and the specific type and form of the container are not limited.

[0075] The standard cutting fluid supply device comprises:

[0076] A standard cutting liquid preparation device, comprising a standard liquid preparation container and a stirring device arranged in the standard liquid preparation container, wherein the pure water in the pure water supply device and the cutting stock liquid in the cutting stock liquid supply device can be injected into the standard liquid preparation container, and the stirring device stirs the liquid in the standard liquid preparation container;

[0077] The standard cutting fluid detection device is used to detect whether the liquid in the standard liquid preparation container meets the use standard of the standard cutting fluid.

[0078] Preferably, the quasi-cutting liquid detection device is configured as a component detection device, which detects whether the concentration of a certain effective component of the liquid in the standard liquid preparation container meets the standard, thereby detecting whether the liquid meets the use standard of the standard cutting liquid.

[0079] Preferably, a first liquid level line and a second liquid level line are provided in the standard liquid preparation container. When the liquid reaches the first liquid level line, it indicates that the total amount of liquid in the standard liquid preparation container has reached a first set amount; when the liquid reaches the second liquid level line, it indicates that the total amount of liquid in the standard liquid preparation container has reached a second set amount; a liquid level sensor is also provided in the standard liquid preparation container, and the liquid level sensor is configured to detect the liquid level of the liquid in the standard liquid preparation container.

[0080] Furthermore, the standard cutting liquid supply device also includes a temperature control component connected to the standard liquid preparation container, and the temperature control component includes a temperature sensor for monitoring the temperature of the liquid in the standard liquid preparation container and a cooling device for cooling the liquid. In this embodiment, the cooling device is configured as an ice machine, the coil of the ice machine passes through the standard liquid preparation container, and the refrigerator of the ice machine is located outside the standard liquid preparation container. The ice machine is a conventional ice machine, which can be purchased on the market, so it is not described here.

[0081] The finished cutting fluid supply device comprises:

[0082] A finished liquid preparation container, into which the pure water in the pure water supply device and the cutting liquid and the recovery liquid in the cutting liquid supply device are injected;

[0083] Finished product cutting fluid detection device, used to detect whether the mixed liquid in the finished product liquid preparation container meets the use standard of the finished product cutting fluid;

[0084] The finished liquid container is used to receive the mixed liquid in the finished liquid preparation container that has been tested and found to be up to standard by the finished cutting liquid testing device, and the finished liquid container is provided with a stirring device, and the stirring device stirs the liquid in the finished liquid container. The liquid in the finished liquid container is the finished cutting liquid mixed with the recovered liquid.

[0085] A third liquid level line and a fourth liquid level line are provided in the finished liquid preparation container. When the liquid in the finished liquid preparation container reaches the third liquid level line, it indicates that the total amount of liquid in the finished liquid preparation container has reached the third set amount; when the liquid reaches the fourth liquid level line, it indicates that the total amount of liquid in the finished liquid preparation container has reached the fourth set amount; a liquid level sensor is also provided in the finished liquid preparation container, and the liquid level sensor is configured to detect the liquid level of the liquid in the finished liquid preparation container.

[0086] Similarly, the finished cutting liquid detection device is configured as a component detection device, which detects whether the concentration of a certain effective component of the mixed liquid in the finished liquid preparation container meets the standard, thereby detecting whether the mixed liquid meets the use standard of the finished cutting liquid.

[0087] In this embodiment, whether it is a standard cutting fluid or a finished cutting fluid, the corresponding cutting fluid is detected by detecting whether the concentration of the effective cost component COD in the corresponding cutting fluid meets the standard, and the concentration of the effective component COD can be set according to the specific situation. In other embodiments, it can also be determined by detecting the concentration of other components, and the principle is the same.

[0088] The finished cutting liquid supply device also includes a temperature control component connected to the finished liquid container, and the temperature control component includes a temperature sensor for monitoring the temperature of the liquid in the finished liquid container and a cooling device for cooling the liquid. The cooling device is also configured as an ice machine, and its principle is the same as that of the cooling device of the standard cutting liquid supply device.

[0089] From the above description, it can be seen that the wafer slicing system of the present invention integrates the preparation of standard cutting fluid, the recovery and treatment of waste fluid, and the preparation of finished cutting fluid, thereby making it easier to control.

[0090] The specific working principle of the wafer slicing system of the present invention is as follows:

[0091] Prepare standard cutting fluid:

[0092] Initially, the pure water supply device and the cutting stock liquid supply device inject pure water and cutting stock liquid into the standard liquid preparation container in a fixed ratio, respectively, until the liquid level sensor detects that the total amount of liquid reaches the first liquid level line of the standard liquid preparation container; at this time, the component detection device detects whether the concentration of the effective component COD of the cutting liquid in the preparation container meets the standard. If it meets the standard, it means that the standard cutting liquid meets the standard and can be put into use. If it does not meet the standard, pure water or cutting stock liquid is injected according to the test results, that is, if the concentration is lower than the set value, the cutting stock liquid is injected, and if the concentration is higher than the set value, pure water is injected until the component concentration detection meets the standard;

[0093] In the subsequent slicing process, when the liquid level sensor detects that the liquid level in the standard liquid preparation container is lower than the second set liquid level line, the pure water supply device and the cutting liquid supply device will inject pure water and cutting liquid into the standard liquid preparation container in a fixed ratio until the total amount of liquid in the preparation container reaches the first liquid level line again; at this time, the component detection device detects whether the concentration of the effective component COD of the cutting liquid in the preparation container meets the standard. If it meets the standard, it means that the standard cutting liquid meets the standard and can be put into use. If it does not meet the standard, the appropriate amount of pure water or cutting liquid will be injected according to the test results until the component concentration test meets the standard.

[0094] Preferably, from the start of liquid injection to the entire subsequent slicing process, the stirring component in the standard liquid preparation container is constantly stirring, which not only allows the liquid in the standard liquid preparation container to be fully mixed, but also prevents precipitation, thereby making the cleaning effect of the standard cutting liquid better, better ensuring the stability of cutting in the knife entry stage, and making the wafer surface cleaner.

[0095] Waste liquid collection, recycling and treatment:

[0096] During the slicing process, the waste liquid generated by the slicing process is collected online in real time and treated; the impurities such as silicon mud left over from the treatment can be discharged according to the process cycle, or according to a set appropriate interval time, or when the total amount reaches a certain set value. The specific discharge amount can be quantitative (i.e., a fixed amount is discharged at a time) or timed (i.e., the discharge time at a time is a fixed value); if too much waste liquid is not needed, the untreated waste liquid can be directly discharged as needed. The collection and recycling of the waste liquid can adopt any known and feasible technology. The discharge of the remaining silicon mud and other impurities and the discharge of the waste liquid are also known and feasible technologies, and are not the invention points of this application, so they will not be described here.

[0097] Turbidity detection of wastewater:

[0098] During the slicing process, the turbidity detection device performs turbidity detection on the recycled waste liquid in real time online. If the detection does not meet the standard (higher than the set turbidity value), the online waste liquid recovery and treatment device will process it again until the turbidity meets the standard. In this embodiment, the turbidity is less than 2000 mg / L, which is up to standard. In other embodiments, the standard value can also be set according to specific requirements. During the slicing process, the operation of recycling and treating the waste liquid and detecting the turbidity of the treated waste liquid is continuously performed online.

[0099] Preparation of finished liquid cutting fluid:

[0100] The recovered liquid with turbidity meeting the standard (lower than or equal to the set turbidity value) and the pure water in the pure water supply device and the cutting stock liquid in the cutting stock liquid supply device are injected into the finished liquid preparation container in a fixed ratio until the liquid level sensor detects that the liquid level in the finished liquid preparation container reaches the third liquid level line; at this time, the component detection device performs component detection on the liquid in the finished liquid preparation container, that is, detects whether the concentration of the component COD in the liquid in the product liquid preparation container meets the standard. If it does not meet the standard, the corresponding amount of pure water or cutting stock liquid is injected according to the detection result, that is, if the COD concentration is lower than the set value, the cutting stock liquid is injected, and if the concentration is higher than the set value, pure water is injected until the COD concentration detection meets the standard; if the detection meets the standard, it is injected into the finished liquid container as the finished cutting liquid mixed with the recovered liquid; when the liquid level sensor detects that the liquid level in the finished liquid preparation container reaches the fourth liquid level line, pure water, cutting stock liquid and recovered liquid with turbidity meeting the standard are injected into the finished liquid preparation container again, and the cycle is repeated.

[0101] Similarly, from the start of liquid injection to the subsequent entire slicing process, the stirring component in the finished liquid container is always in a stirring state.

[0102] During the stirring process, the stirring components in the standard liquid preparation container and the finished liquid container will generate heat, which will increase the temperature of the liquid in the container; the temperature sensor detects the temperature of the liquid in the container in real time. When the temperature exceeds the maximum set value, the refrigeration machine of the ice machine will start cooling, so that the temperature of the coil in the standard liquid preparation container will decrease, thereby cooling the liquid.

[0103] The dynamic regulation group is connected to the standard liquid preparation container and the finished liquid container; during slicing, according to the control of the dynamic regulation group, at the knife-entering stage of a crystal rod, the standard cutting liquid is provided by the standard cutting liquid supply device; at other slicing stages other than the knife-entering stage, the finished cutting liquid supply device is switched to provide finished cutting liquid mixed with recovery liquid to enter the slicer for spraying; until the slicing process of the crystal rod is completed; when it is time to slice the next crystal rod, the dynamic frequency conversion regulation component cycles the above switching control.

[0104] The switching control of the dynamic control group can be any known and feasible technology. The use of the dynamic control group to switch between different cutting fluids can reduce the labor intensity of personnel.

[0105] Standard cutting fluid is used in the knife-entering stage, because the standard cutting fluid does not contain granular impurities, which can better rinse away impurities such as silicon powder and silicon mud on the cutting surface of the wafer, avoiding the risk of impurity particles contaminating the cutting fluid and causing poor knife entry, which not only improves the cleanliness of the wafer surface, but also ensures the stability of the cutting process and improves the TTV / WARP cutting yield of the wafer; and the finished cutting fluid is not only the recycled waste liquid, but also a mixture of pure water and cutting stock liquid, which can also ensure the overall stability of the finished cutting fluid, that is, to ensure the stability of the slicing process in other slicing stages besides knife entry, and then ensure the overall surface cleanliness of the wafer and the TTV / WARP cutting yield.

[0106] Online recycling of the waste liquid generated during the slicing process and treating it into reusable recycled liquid can also prevent the waste liquid from accumulating in the slicer, thereby improving the cleanliness of the slicer. In this way, the stability of the slicing process can be further improved, thereby improving the cleanliness of the wafer surface and the slicing quality, that is, improving the wafer TTV / WARP cutting yield.

[0107] from Figure 2 , Figure 3 By comparison, compared Figure 1 The wafer obtained by conventional slicing in the present invention and the wafer obtained by the slicing method and slicing system of the present invention (such as Figure 2 (As shown) its surface is much cleaner, that is, the cleanliness level is much higher.

[0108] from Figure 4By comparison, it can be seen that the TTV value B of the wafer obtained by the slicing method and slicing system of the present invention is much lower than the TTV value A of the wafer obtained by the conventional slicing method, indicating that the TTV cutting yield of the wafer can be greatly improved by adopting the present invention.

[0109] from Figure 5 By comparison, it can be seen that the WARP value D of the wafer obtained by the slicing method and slicing system of the present invention is much lower than the WARP value C of the wafer obtained by the conventional slicing method, indicating that the WARP cutting yield of the wafer can be greatly improved by adopting the present invention.

[0110] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A wafer slicing method, characterized in that: include: During the slicing process, the cutting fluid in the knife-entering stage uses standard cutting fluid, and the cutting fluid in other stages other than the knife-entering stage uses finished cutting fluid mixed with recycled fluid.

2. The wafer slicing method according to claim 1, characterized in that: The standard cutting fluid is prepared by mixing and stirring pure water and cutting stock fluid, and the finished cutting fluid is prepared by mixing and stirring the recovered fluid, pure water and cutting stock fluid.

3. The wafer slicing method according to claim 2, characterized in that: The preparation method of the standard cutting fluid is: pure water and cutting stock fluid are mixed and stirred in a fixed ratio, and then the mixed liquid is tested to see whether it meets the standard for use of the standard cutting fluid. If it meets the standard, it means that the mixed liquid can be used as the standard cutting fluid; If it does not meet the standard, pure water or cutting solution will be injected according to the test results, and real-time testing will be carried out during the injection process until it meets the standard.

4. The wafer slicing method according to claim 3, characterized in that: Initially, pure water and cutting fluid are mixed in a fixed ratio. When the total amount of pure water and cutting fluid reaches the first set amount, the addition of water and cutting fluid is stopped, and then the mixed liquid is tested to see if it meets the standard for the use of the standard cutting fluid. When the test is up to standard, the addition of water and cutting fluid is stopped; Preferably, during the slicing process, when the standard cutting liquid is less than the second set amount, pure water and cutting stock liquid are added to the standard cutting liquid in a fixed ratio and mixed and stirred, and when the total amount of the liquid reaches the first set value, the addition of water and cutting liquid is stopped again, and then the mixed liquid is tested to see if it meets the standard for the use of the standard cutting liquid; Preferably, whether the mixed liquid meets the use standard of the standard cutting fluid is detected by detecting whether the concentration of a certain active ingredient in the mixed liquid reaches a set standard.

5. The wafer slicing method according to claim 2, 3 or 4, characterized in that: During the slicing process, the waste liquid generated by the slicing is recovered and treated, and the turbidity of the treated waste liquid is tested. If the turbidity meets the standard, it can be used as the recovered liquid; if it does not meet the standard, it is treated again until its turbidity meets the standard; Preferably, the recovery liquid, pure water and cutting stock liquid are injected into the finished liquid preparation container according to a fixed ratio. When the total amount of the mixed liquid in the finished liquid preparation container reaches a third set amount, the injection is stopped to detect whether the mixed liquid reaches the use standard of the finished cutting liquid. If it does not reach the standard, pure water or cutting stock liquid is injected again according to the test results. The injection process is tested in real time until the mixed liquid reaches the use standard of the finished cutting liquid. Preferably, the mixed liquid in the finished liquid preparation container that has been tested to meet the standards is injected into the finished liquid container, and the liquid in the finished liquid container is kept in a stirred state. The liquid in the finished liquid container is the finished cutting liquid mixed with the recovery liquid; preferably, whether the mixed liquid meets the use standard of the finished cutting liquid is detected by detecting whether the concentration of a certain active ingredient in the mixed liquid in the finished liquid preparation container reaches the set standard; Preferably, when the total amount of liquid in the finished liquid preparation container is less than the fourth set amount, the injection into the finished liquid container is suspended; then pure water, cutting raw liquid and the recovered liquid that has met the inspection standards are injected into the finished liquid preparation container in a fixed ratio until the total amount of liquid reaches the third set amount again, and then the injection is suspended to detect whether the mixed liquid meets the use standards of the finished cutting liquid, and the above cycle is repeated.

6. The wafer slicing method according to any one of claims 2 to 5, characterized in that: During the stirring process of the standard cutting fluid and the finished cutting fluid, the temperature of the liquid is detected in real time. When the temperature exceeds the maximum value of the set temperature, the liquid is cooled so that the temperature of the liquid is within the set temperature range.

7. A wafer slicing system, characterized in that: include; Standard cutting fluid supply device, can provide standard cutting fluid; Finished cutting fluid supply device, which can provide finished cutting fluid mixed with recycled fluid; A dynamic control group connected to the standard cutting fluid supply device and the finished cutting fluid supply device; According to the control of the dynamic regulation group, in the slicing entry stage, the standard cutting liquid supply device provides standard cutting liquid, and in other slicing stages other than the slicing entry stage, the finished cutting liquid supply device switches to provide finished cutting liquid mixed with recovery liquid.

8. The wafer slicing system according to claim 7, characterized in that: It also includes a pure water supply device connected to the standard cutting liquid supply device and the finished cutting liquid supply device, a cutting stock liquid supply device, and an online waste liquid recovery and treatment device connected to the finished cutting liquid supply device, wherein the online waste liquid recovery and treatment device is configured to recover and treat the waste liquid generated during the slicing process online to obtain the recovered liquid; the standard cutting liquid supply device receives the pure water supplied by the pure water supply device and the cutting stock liquid supplied by the cutting stock liquid supply device, and mixes them into the qualified standard cutting liquid; The standard cutting liquid supply device receives the pure water supplied by the pure water supply device, the cutting liquid supplied by the cutting liquid supply device, and the recovered liquid provided by the online waste liquid recovery and treatment device, and mixes them into the qualified finished cutting liquid mixed with the recovered liquid; Preferably, the wafer slicing system further comprises a turbidity detection device, which performs turbidity detection on the waste liquid recovered and treated by the online waste liquid recovery and treatment device.

9. The wafer slicing system according to claim 8, characterized in that: The standard cutting fluid supply device comprises: A standard cutting liquid preparation device, comprising a standard liquid preparation container and a stirring device arranged in the standard liquid preparation container, wherein the pure water in the pure water supply device and the cutting stock liquid in the cutting stock liquid supply device can be injected into the standard liquid preparation container, and the stirring device stirs the liquid in the standard liquid preparation container; A standard cutting fluid detection device is used to detect whether the liquid in the standard liquid preparation container meets the standard for use of the standard cutting fluid; Preferably, the quasi-cutting fluid detection device is configured as a component detection device; Preferably, a first liquid level line and a second liquid level line are provided in the standard liquid dispensing container. When the liquid reaches the first liquid level line, it indicates that the total amount of liquid in the standard liquid dispensing container has reached a first set amount; when the liquid reaches the second liquid level line, it indicates that the total amount of liquid in the standard liquid dispensing container has reached a second set amount; a liquid level sensor is also provided in the standard liquid dispensing container, and the liquid level sensor is configured to detect the liquid level of the liquid in the standard liquid dispensing container; Preferably, the standard cutting liquid supply device also includes a temperature control component connected to the standard liquid preparation container, and the temperature control component includes a temperature sensor for monitoring the temperature of the liquid in the standard liquid preparation container and a cooling device for cooling the liquid.

10. The wafer slicing system according to claim 9, characterized in that: The finished cutting fluid supply device comprises: A finished liquid preparation container, into which the pure water in the pure water supply device and the cutting liquid and the recovery liquid in the cutting liquid supply device are injected; Finished product cutting fluid detection device, used to detect whether the mixed liquid in the finished product liquid preparation container meets the use standard of the finished product cutting fluid; A finished liquid container is used to receive the mixed liquid in the finished liquid preparation container that has been tested by the finished cutting liquid testing device and has met the standards. The finished liquid container is provided with a stirring device, and the stirring device stirs the liquid in the finished liquid container. The liquid in the finished liquid container is the finished cutting liquid mixed with the recovery liquid. Preferably, a third liquid level line and a fourth liquid level line are provided in the finished liquid mixing container. When the liquid in the finished liquid mixing container reaches the third liquid level line, it indicates that the total amount of liquid in the finished liquid mixing container has reached the third set amount; when the liquid reaches the fourth liquid level line, it indicates that the total amount of liquid in the finished liquid mixing container has reached the fourth set amount; a liquid level sensor is also provided in the finished liquid mixing container, and the liquid level sensor is configured to detect the liquid level of the liquid in the finished liquid mixing container; Preferably, the finished cutting fluid detection device is configured as a component detection device; Preferably, the finished cutting liquid supply device also includes a temperature control component connected to the finished liquid container, and the temperature control component includes a temperature sensor for monitoring the temperature of the liquid in the finished liquid container and a cooling device for cooling the liquid.

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