Wafer separation device and wafer separation method

Abstract

The invention discloses a wafer separation device and a wafer separation method. The wafer separating device comprises a container used for bearing a crystal ingot; the ultrasonic vibrator is arranged on the bottom wall of the container and used for providing primary high-frequency ultrasonic vibration for the crystal ingot immersed in the liquid in the container so as to pre-strip the crystal ingot; the stripping mechanism comprises a lifting assembly and an ultrasonic tool head, the lifting assembly is connected with the ultrasonic tool head and used for driving the ultrasonic tool head to make contact with the end face of the crystal ingot, and the ultrasonic tool head is used for providing secondary high-frequency ultrasonic vibration for the crystal ingot when making contact with the end face of the crystal ingot so as to strip the wafer from the crystal ingot. Through the above mode, the wafer separation device provided by the invention optimizes the uniformity of crack propagation and the accuracy of the stripping process through the combination of liquid-conducted overall ultrasound and direct contact ultrasound, and significantly improves the stability and efficiency of wafer stripping.

Description

Technical Field

[0001] This application relates to the technical field of wafer peeling, and particularly to a wafer separation device and a wafer separation method. Background Art

[0002] In the field of silicon carbide wafer manufacturing, ultrasonic peeling technology has been widely used due to its high efficiency and high compatibility. However, common liquid-conducted ultrasonic peeling technology and contact ultrasonic technology both have certain limitations in practical applications.

[0003] First, the liquid-conducted ultrasonic peeling technology (Patent CN108161215B) immerses an ingot modified by laser inside into a liquid and places it on an ultrasonic oscillator. By using an ultrasonic vibration unit to generate ultrasonic vibration close to the natural frequency of the ingot, the vibration is transmitted to the ingot through the liquid to achieve wafer peeling. Although this liquid-conducted ultrasonic peeling technology can ensure the uniformity of ultrasonic action, the liquid absorbs a large amount of ultrasonic energy, resulting in low transmission efficiency. High-power equipment is required to compensate for energy loss, which brings problems such as high energy consumption and shortened equipment life.

[0004] Second, the contact ultrasonic technology (Patent CN115029785A) adjusts the frequency and amplitude of ultrasonic waves to directly apply ultrasonic vibration and tensile or shear external forces to the separation object. Under the synergistic action of the two, after the cracks inside the ingot expand, the wafer is peeled off. It has high energy utilization efficiency and short peeling time. However, due to the over-concentration of ultrasonic energy, the sudden introduction of stress is likely to cause local damage to the wafer, resulting in a decline in peeling quality and limited yield. Therefore, the current technology has deficiencies in terms of equipment life, peeling quality, and yield. Summary of the Invention

[0005] This application mainly provides a wafer separation device and a wafer separation method to solve the problem that existing wafer peeling solutions cannot balance the uniform crack expansion and reduce the wafer breakage rate.

[0006] To solve the above technical problems, a technical solution adopted by this application is: to provide a wafer separation device. The wafer separation device includes: a container for carrying an ingot; an ultrasonic oscillator disposed on the bottom wall of the container for providing a primary high-frequency ultrasonic vibration to the ingot immersed in the liquid in the container to pre-peel the ingot; a peeling mechanism including a lifting assembly and an ultrasonic tool head. The lifting assembly is connected to the ultrasonic tool head and is used to drive the ultrasonic tool head to contact the end face of the ingot. The ultrasonic tool head is used to provide a secondary high-frequency ultrasonic vibration to the ingot when contacting the end face of the ingot to peel off the wafer from the ingot.

[0007] In some embodiments, the ultrasonic tool head is further configured to adsorb on the end face of the ingot, and the lifting assembly is further configured to apply an upward lifting force when the ultrasonic tool head provides secondary high-frequency ultrasonic vibration to the ingot.

[0008] In some embodiments, the wafer separation device further includes a liquid control member connected to the container. The liquid control member is configured to inject liquid into the container before the ultrasonic vibrator performs pre-stripping, and the liquid level is not lower than the end face of the ingot.

[0009] The liquid control member is further configured to lower the liquid level in the container below the end face of the ingot after the ingot completes pre-stripping and before the ultrasonic tool head contacts the end face of the ingot.

[0010] In some embodiments, the wafer separation device further includes a base disposed in the container. The base is provided with an adsorption air duct, and the base is configured to carry the ingot.

[0011] Wherein, after the ingot completes pre-stripping, the liquid control member lowers the liquid level in the container below the end face of the base, and the base adsorbs and fixes the ingot.

[0012] In some embodiments, the lifting speed of the ultrasonic tool head is 0.1-1 mm / s.

[0013] In some embodiments, the wafer separation device further includes a vision detection member. The vision detection member is configured to perform vision detection on the ingot during the pre-stripping process, and stop the operation of the ultrasonic vibrator when it detects that the crack propagation of the ingot reaches the target state.

[0014] In some embodiments, the vision detection member is further configured to monitor the stripping state of the ultrasonic tool head on the wafer, and stop the ultrasonic operation of the ultrasonic tool head when the wafer stripping is completed.

[0015] In some embodiments, the ultrasonic frequency of the ultrasonic vibrator is 40-80 kHz, its ultrasonic power is 100-500 W, and its ultrasonic vibration time is 30-90 s.

[0016] The ultrasonic frequency of the ultrasonic tool head is 20 kHz-40 kHz, and its ultrasonic amplitude is 5 μm-20 μm.

[0017] To solve the above technical problems, another technical solution adopted by this application is: to provide a wafer separation method. The wafer separation method includes: providing primary high-frequency ultrasonic vibration to an ingot immersed in liquid through an ultrasonic vibrator to perform pre-stripping on the ingot; driving an ultrasonic tool head to contact the end face of the ingot and perform secondary high-frequency ultrasonic vibration to strip a wafer from the ingot.

[0018] In some embodiments, driving the ultrasonic tool head to contact the end face of the ingot and perform secondary high-frequency ultrasonic vibration to strip wafers from the ingot includes:

[0019] Driving the ultrasonic tool head to contact and adsorb the end face of the ingot;

[0020] Applying secondary high-frequency ultrasonic vibration to the ingot and simultaneously applying an upward lifting force to the ingot to strip wafers from the ingot.

[0021] The beneficial effects of this application are as follows: Different from the prior art, this application discloses a wafer separation device and a wafer separation method. By first immersing the ingot in the liquid in the container and using the liquid to conduct high-frequency ultrasonic vibration, the vibration energy transmitted by the liquid covers the entire immersed surface of the ingot, realizing the overall expansion of cracks at its modified layer to pre-strip the ingot. At this time, the stripping layer is not completely formed, so the equipment power of the ultrasonic oscillator does not need to reach the ultrasonic power in the traditional liquid-conducted ultrasonic stripping technology relatively speaking. That is, a lower ultrasonic vibration power can ensure uniform crack expansion; then the end face of the ingot is exposed above the liquid level, and the lifting assembly drives the ultrasonic tool head to contact the end face of the ingot. The ultrasonic tool head performs secondary high-frequency ultrasonic vibration on the ingot, and then through contact ultrasonic treatment, the stripping of the wafer is completed. At this time, because the cracks at the modified layer of the ingot have been pre-expanded, the stress required to introduce secondary ultrasonic vibration is relatively lower than that of the traditional contact ultrasonic stripping technology. The secondary vibration preferentially expands these pre-existing cracks through the resonance effect, thus effectively reducing the risk of causing local damage to the wafer. Therefore, through the combination of overall ultrasonic conduction by liquid and direct contact ultrasonic in this application, the uniformity of crack expansion and the accuracy of the stripping process are optimized, significantly improving the stability and efficiency of wafer stripping. Description of the Drawings

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings, where:

[0023] Figure 1 is a schematic structural diagram of an embodiment of the wafer separation device provided by the present application.

[0024] Figure 2 is a schematic flow diagram of an embodiment of the wafer separation method provided by the present application;

[0025] Figure 3 is Figure 2Schematic flowchart of an embodiment of step 20 in the wafer separation method. Detailed implementation manners

[0026] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0027] The terms "first", "second", and "third" in the embodiments of the present application are only used for descriptive purposes, and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second", and "third" may explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or units inherent to these processes, methods, products, or devices.

[0028] Referring to "embodiment" herein means that a specific feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0029] The present application provides a wafer separation device 100. Refer to Figure 1 , Figure 1 which is a schematic structural diagram of an embodiment of the wafer separation device provided by the present application.

[0030] The wafer separation device 100 includes a container 10, an ultrasonic oscillator 20, and a peeling mechanism 30. The container 10 is used to carry an ingot 01. The ultrasonic oscillator 20 is disposed on the container 10 and is used to provide a primary high-frequency ultrasonic vibration to the ingot 01 immersed in the liquid in the container 10 to pre-peel the ingot 01. The peeling mechanism 30 includes a lifting assembly (not shown in the figure) and an ultrasonic tool head 31. The lifting assembly is connected to the ultrasonic tool head 31 and is used to drive the ultrasonic tool head 31 to contact the end face of the ingot 01. The ultrasonic tool head 31 is used to provide a secondary high-frequency ultrasonic vibration to the ingot 01 when contacting the end face of the ingot 01 to peel a wafer 02 from the ingot 01.

[0031] The container 10 is made of corrosion-resistant stainless steel or polytetrafluoroethylene material and is used to carry the liquid and the ingot 01. The ingot 01 can be directly placed on the bottom wall of the container 10 or fixed by a support platform or a fixture in the container 10, etc., so that the ingot to be processed can be fixed more firmly to improve the peeling efficiency of the ingot.

[0032] The bottom wall or the side wall of the container 10 is designed with a liquid circulation channel. Deionized water or other liquid media can be injected into it through this liquid circulation channel, and the fluidity and temperature stability of the liquid can be maintained through a liquid circulation system. The selection of the liquid needs to have high ultrasonic conductivity. Its function is not only to transmit vibration energy but also to continuously cool the ingot during the peeling process to avoid damage to the wafer structure caused by local overheating.

[0033] In this embodiment, the side wall of the container 10 is provided with a liquid inlet hole 101 and a liquid outlet hole 102. The liquid inlet hole 101 is higher than the liquid outlet hole 102, and the liquid outlet hole 102 is arranged close to the bottom wall of the container 10. The liquid can be circulated into and discharged from the container 10 through the liquid inlet hole 101 and the liquid outlet hole 102.

[0034] Specifically, the wafer separation device 100 further includes a liquid control member (not shown in the figure) connected to the container 10. The liquid inlet end of the liquid control member is connected to the liquid inlet hole 101, and its liquid outlet end is connected to the liquid outlet hole 102. The liquid control member is used to inject liquid into the container 10 before the ultrasonic oscillator 20 performs pre-peeling, and the liquid level is not lower than the end face of the ingot 01. The liquid control member is also used to lower the liquid level in the container 10 below the end face of the ingot 10 or empty the liquid after the ingot completes pre-peeling and before the ultrasonic tool head 31 contacts the end face of the ingot 01.

[0035] The liquid control member can be a liquid pump or a liquid circulation system, etc. It can control the injection of liquid into the container 10 and the discharge of liquid from the container 10. After the liquid in the container 10 is discharged, it is convenient for the ultrasonic tool head 31 to perform contact ultrasonic peeling.

[0036] Optionally, a liquid pipe can also be set to insert into the container 10, and the liquid can be injected into and discharged from the container 10 through the liquid pipe.

[0037] In this embodiment, the wafer separation device 100 further includes a base 12 disposed in the container 10. The base 12 is used to support the ingot 01 and can make the ingot 01 have a certain height relative to the bottom wall of the container 10, so that even if there is liquid residue after drainage, it will not affect the subsequent secondary high-frequency ultrasonic vibration process.

[0038] Optionally, the base 12 can be set to have a lifting function to immerse the ingot 01 into the liquid or expose it from the liquid by its own lifting, which is equivalent to canceling the setting of injecting and draining liquid into the container 10.

[0039] In this embodiment, an adsorption air duct is further provided on the base 12, and the base 12 is used to carry and adsorb and fix the ingot 01; wherein, after the ingot 01 is pre-peeled, the liquid level in the container 10 is lowered below the end face of the base 12 by the liquid control member, and the base 12 adsorbs and fixes the ingot 01 to ensure the stability of the ingot 01 during the subsequent contact ultrasonic peeling process and improve the peeling efficiency.

[0040] The ultrasonic oscillator 20 is fixed to the side wall or the bottom wall of the container 10 and is connected to the AC power supply 22. Its vibration frequency can be set to 20 kHz to 100 kHz, and the specific value can be adjusted according to the material (such as silicon, silicon carbide) and thickness of the ingot 01. After the ingot 01 is immersed in the liquid, the ultrasonic oscillator 20 is started to generate primary high-frequency ultrasonic vibration, and the vibration energy is transmitted to the surface of the ingot 01 through the liquid medium, and then the cracks in the ingot 01 are initially expanded. The depth of these micro-cracks is controllable, which can weaken the structure of the ingot 01 without penetrating the wafer, realizing the overall expansion of the cracks, thereby laying a uniform stress distribution foundation for the subsequent peeling.

[0041] The peeling mechanism 30 includes a lifting component and an ultrasonic tool head 31. The lifting component can adopt a servo motor-driven precision lead screw structure, or the lifting component can also be a robotic arm, which can control the ultrasonic tool head 31 to move vertically with micron-level precision to ensure its stable contact with the end face of the ingot 01.

[0042] The end face shape of the ultrasonic tool head 31 is designed to match the end face of the ingot 01, and a piezoelectric ceramic transducer is integrated inside it, which can generate secondary ultrasonic vibration with the same frequency or lower frequency than the ultrasonic oscillator 20. When the ultrasonic tool head 31 contacts the ingot 01, the energy of the secondary high-frequency ultrasonic vibration directly acts on the end face of the ingot 01, further expanding the micro-cracks formed by pre-peeling inside it, and at the same time making the cracks extend uniformly along the inside of the ingot 01 through the conduction of the vibration wave, and finally the complete peeling of the wafer 02 can be realized.

[0043] In this embodiment, the ultrasonic tool head 31 is further used to adsorb on the end face of the ingot 01, and the lifting component is further used to apply an upward lifting force when the ultrasonic tool head 31 provides secondary high-frequency ultrasonic vibration to the ingot 01, so as to further improve the efficiency of wafer 01 peeling and the uniformity of wafer peeling in cooperation with the contact ultrasonic peeling technology.

[0044] The ultrasonic tool head 31 is also provided with an adsorption air passage. When it contacts the end face of the ingot 01, the ingot 01 is also negatively adsorbed through the adsorption air passage, so as to maintain stable contact with the end face of the ingot 01. And when secondary high-frequency ultrasonic vibration occurs, the lifting component can further apply a lifting force to the ingot 01 based on this adsorption connection relationship. At the same time, because the base 12 also adsorbs and fixes the ingot 01, it can further ensure the stability of the peeling process and improve the uniformity of wafer peeling.

[0045] At the same time, before the liquid control member performs secondary ultrasonic treatment on the ingot 01, the liquid level in the container 10 is at least lowered below the end face of the base 12 or the liquid is emptied, so as to avoid liquid entering the adsorption air passage when the base 12 and the ultrasonic tool head 31 adsorb the ingot 01.

[0046] The lifting speed of the ultrasonic tool head 31 is 0.1-1 mm / s, and it can be specifically set to 0.1 mm / s, 0.2 mm / s, 0.3 mm / s, 0.4 mm / s, 0.5 mm / s, 0.6 mm / s, 0.7 mm / s, 0.8 mm / s, 0.9 mm / s or 1.0 mm / s. This lifting speed range helps to stabilize the wafer peeling process, avoid excessive crack propagation, and avoid incomplete wafer peeling caused by too fast lifting speed.

[0047] The ingot 01 is placed in the container 10 after being subjected to laser modification treatment. After laser modification in the ingot 01, a modified layer is formed. External force needs to be applied to introduce stress, so that the cracks in it expand and connect with each other at the modified layer, and finally a complete peeling layer is formed. This peeling layer is the required wafer 02.

[0048] In this application, the ingot 01 is first immersed in the liquid in the container 10, and high-frequency ultrasonic vibration is conducted through the liquid. The vibration energy transmitted by the liquid covers the entire immersed surface of the ingot 01, realizing the overall expansion of the cracks at the modified layer thereof to pre-strip the ingot 01. At this time, the stripping layer is not completely formed, so the equipment power of the ultrasonic oscillator 20 does not need to reach the ultrasonic power in the traditional liquid-conduction ultrasonic stripping technology relatively speaking. That is, a lower ultrasonic vibration power can ensure uniform crack expansion; then the end face of the ingot 01 is exposed above the liquid level, and the lifting assembly drives the ultrasonic tool head 31 to contact the end face of the ingot 01. The ultrasonic tool head 31 performs secondary high-frequency ultrasonic vibration on the ingot, and then through contact ultrasonic treatment, the stripping of the wafer 02 is completed. At this time, because the cracks at the modified layer of the ingot 01 have been pre-expanded, the stress required to introduce the secondary ultrasonic vibration is relatively lower than that of the traditional contact ultrasonic stripping technology. The secondary vibration preferentially expands these pre-existing cracks through the resonance effect, thereby effectively reducing the risk of causing local damage to the wafer 02. Therefore, through the combination of the overall ultrasonic wave conducted by the liquid and the direct contact ultrasonic wave in this application, the uniformity of crack expansion and the accuracy of the stripping process are optimized, and the stability and efficiency of wafer stripping are significantly improved.

[0049] Through the innovative dual ultrasonic vibration design and the synergistic effect of the liquid medium in this application, precise control of cracks and significant reduction of the breakage rate during the wafer stripping process are achieved. The structural parameters (such as vibration frequency, contact pressure) of each component of the wafer separation device 100 can be flexibly adjusted according to different material characteristics, and it has the advantages of high efficiency, precision, simplicity and broad industrial application prospects in the wafer stripping processing of new-generation semiconductor materials such as SiC and diamond.

[0050] Among them, the ultrasonic frequency of the ultrasonic tool head 31 is less than or equal to the ultrasonic frequency of the ultrasonic oscillator 20. After the crack expansion is realized through the liquid-conduction ultrasonic stripping technology, the contact ultrasonic stripping technology can strip the wafer 02 with a smaller ultrasonic frequency, further reducing the risk of causing damage to the wafer 02.

[0051] In this embodiment, the ultrasonic frequency of the ultrasonic oscillator 20 is 40 - 80 kHz, its ultrasonic power is 100 - 500 W, and its ultrasonic vibration time is 30 - 90 s. During pre-stripping, the ultrasonic oscillator applies ultrasonic waves to the whole ingot 01 at an ultrasonic frequency of 40 - 80 kHz and an ultrasonic power of 100 - 500 W, prompting the cracks at the modified layer to initially expand along the crystal C plane, and stopping after controlling the ultrasonic vibration time within 30 - 90 s so that the crack expansion reaches the expected effect.

[0052] Specifically, the ultrasonic frequency, ultrasonic power and ultrasonic vibration duration of the ultrasonic oscillator 20 can be adaptively set based on the size specifications of the ingot 01 and the wafer 02 to ensure uniform and efficient crack expansion.

[0053] The ultrasonic frequency of the ultrasonic tool head 31 is 20 kHz - 40 kHz, and its ultrasonic amplitude is 5 μm - 20 μm. During the secondary ultrasonic peeling, the ultrasonic tool head 31 applies secondary ultrasonic waves to the ingot 01 at an ultrasonic frequency of 20 kHz - 40 kHz and an ultrasonic amplitude of 5 μm - 20 μm to peel the wafer 02. When the ultrasonic amplitude reaches 20 μm, the vacuum degree of the adsorption air channel can be adjusted to -80 kPa or higher to ensure adsorption stability and avoid uneven peeling.

[0054] Furthermore, the wafer separation device 100 further includes a visual detection component (not shown in the figure). The visual detection component is used to perform visual detection on the ingot 01 during the pre-peeling process and stop the operation of the ultrasonic oscillator 20 when the crack propagation of the ingot is detected to reach the target state.

[0055] In addition, the visual detection component is also used to monitor the peeling state of the ultrasonic tool head 31 on the wafer and stop the ultrasonic operation of the ultrasonic tool head 31 when the wafer peeling is completed.

[0056] The visual detection component can be a camera or a webcam, etc. During the pre-peeling and secondary ultrasonic peeling processes, it monitors the states of the ingot 01 and the wafer 02 in real time. During pre-peeling, it monitors the crack propagation state on the surface of the ingot 01. During the secondary ultrasonic peeling process, it monitors the separation interface between the ingot 01 and the peeled wafer 02 in real time. When it reaches the corresponding target state, it pauses the corresponding ultrasonic oscillator 20 or ultrasonic tool head 31, which can peel the wafer 02 more intelligently and efficiently.

[0057] Based on this, the present application also provides a wafer separation method. This wafer separation method is applied to the wafer separation device 100 as described above. Refer to Figure 2 , Figure 2 is a schematic flowchart of an embodiment of the wafer separation method provided by the present application. This wafer separation method includes:

[0058] Step 10: Provide primary high-frequency ultrasonic vibration to the ingot immersed in the liquid through the ultrasonic oscillator to pre-peel the ingot.

[0059] The ingot 01 after laser modification treatment is placed on the base 12 in the container 10, and liquid is injected into the container 10 through the liquid control component. The liquid level is at least flush with the end face of the ingot 01. Then, the ultrasonic oscillator 20 is started, and high-frequency ultrasonic vibration is transmitted through the liquid to achieve the overall expansion of the cracks at the modified layer of the ingot 01 to pre-peel the ingot 01.

[0060] Step 20: Drive the ultrasonic tool head to contact the end face of the ingot and perform secondary high-frequency ultrasonic vibration to peel the wafer from the ingot.

[0061] The liquid discharging member discharges the liquid in the container 10, and the lifting assembly drives the ultrasonic tool head 31 to contact and adsorb the end face of the ingot 01, performing secondary high-frequency ultrasonic vibration on the ingot, and then completing the peeling of the wafer 02 through contact ultrasonic treatment.

[0062] Specifically, referring to Figure 3 , Figure 3 is Figure 2 a schematic flow chart of an embodiment of step 20 in the wafer separation method. Step 20 specifically includes:

[0063] Step 21: Drive the ultrasonic tool head to contact and adsorb the end face of the ingot.

[0064] The ultrasonic tool head 31 contacts and adsorbs the end face of the ingot 01, and the base 12 also adsorbs the bottom face of the ingot 01 to ensure the stability of the peeling process and improve the uniformity of wafer peeling.

[0065] Step 22: Apply secondary high-frequency ultrasonic vibration to the ingot and simultaneously apply an upward lifting force to the ingot to peel the wafer from the ingot.

[0066] The ultrasonic tool head 31 applies secondary high-frequency ultrasonic vibration to the ingot. At the same time, the lifting assembly also applies an upward lifting force to the ingot 01 through the ultrasonic tool head 31 to further improve the efficiency of peeling the wafer 01 and the uniformity of wafer peeling in cooperation with the contact ultrasonic peeling technology.

[0067] Different from the prior art, the present application discloses a wafer separation device and a wafer separation method. By first immersing the ingot in the liquid in the container and using the liquid to conduct high-frequency ultrasonic vibration, the vibration energy transmitted by the liquid covers the entire immersed surface of the ingot, realizing the overall expansion of cracks at its modified layer to pre-peel the ingot. At this time, the peeling layer is not completely formed, so the equipment power of the ultrasonic oscillator does not need to reach the ultrasonic power in the traditional liquid-conducted ultrasonic peeling technology relatively speaking, that is, ensuring uniform crack expansion with a relatively low ultrasonic vibration power is sufficient; then the end face of the ingot is exposed above the liquid surface, and the lifting assembly drives the ultrasonic tool head to contact the end face of the ingot. The ultrasonic tool head performs secondary high-frequency ultrasonic vibration on the ingot, and then completes the peeling of the wafer through contact ultrasonic treatment. At this time, because the cracks at the modified layer of the ingot have been pre-expanded, the stress required to introduce the secondary ultrasonic vibration is relatively lower than that of the traditional contact ultrasonic peeling technology. The secondary vibration preferentially expands these pre-existing cracks through the resonance effect, thus effectively reducing the risk of causing local damage to the wafer. Therefore, through the combination of the overall ultrasonic conduction through the liquid and the direct contact ultrasonic, the present application optimizes the uniformity of crack expansion and the accuracy of the peeling process, significantly improving the stability and efficiency of wafer peeling.

[0068] The above has introduced in detail the wafer separation device 100 provided in the embodiments of the present application. Specific examples are applied in the present application to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the technical solution and its core idea of the present application; those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A wafer separation device, characterized in that: include: A container for holding the ingot; an ultrasonic vibrator, disposed on the bottom wall of the container, for providing an initial high-frequency ultrasonic vibration to the ingot immersed in the liquid in the container, so as to pre-strip the ingot; The stripping mechanism includes a lifting assembly and an ultrasonic tool head, wherein the lifting assembly is connected to the ultrasonic tool head and is used to drive the ultrasonic tool head to contact the end face of the ingot, and the ultrasonic tool head is used to provide secondary high-frequency ultrasonic vibration to the ingot when contacting the end face of the ingot, so as to strip a wafer from the ingot.

2. The wafer separation device according to claim 1, characterized in that: The ultrasonic tool head is also used to be adsorbed on the end surface of the crystal ingot, and the lifting assembly is also used to apply an upward lifting force when the ultrasonic tool head provides secondary high-frequency ultrasonic vibration to the crystal ingot.

3. The wafer separation device according to claim 2, characterized in that: The wafer separation device further comprises a liquid control member connected to the container, the liquid control member being used to inject liquid into the container before the ultrasonic vibrator performs pre-stripping, and the liquid level is not lower than the end surface of the ingot; The liquid control member is further used for lowering the liquid level in the container to below the end surface of the crystal ingot after the pre-stripping of the crystal ingot is completed and before the ultrasonic tool head contacts the end surface of the crystal ingot.

4. The wafer separation device according to claim 3, characterized in that: The wafer separation device further comprises a base disposed in the container, the base being provided with an adsorption air channel, and the base being used to carry the crystal ingot; Wherein, the liquid control component lowers the liquid level in the container to below the end surface of the base after the pre-stripping of the crystal ingot is completed, and the base absorbs and fixes the crystal ingot.

5. The wafer separation device according to claim 2, characterized in that: The lifting speed of the ultrasonic tool head is 0.1-1 mm / s.

6. The wafer separation device according to claim 1, characterized in that: The wafer separation device further includes a visual inspection component, which is used to perform visual inspection on the crystal ingot during the pre-stripping process and stop the operation of the ultrasonic vibrator when it is detected that the crack extension of the crystal ingot reaches a target state.

7. The wafer separation device according to claim 6, characterized in that: The visual detection component is also used to monitor the peeling state of the wafer by the ultrasonic tool head, and stop the ultrasonic operation of the ultrasonic tool head when the wafer peeling is completed.

8. The wafer separation device according to claim 1, characterized in that: The ultrasonic frequency of the ultrasonic vibrator is 40-80kHz, the ultrasonic power is 100-500W, and the ultrasonic vibration time is 30-90s; The ultrasonic frequency of the ultrasonic tool head is 20kHz-40kHz, and the ultrasonic amplitude is 5μm-20μm.

9. A wafer separation method, characterized in that: The wafer separation method comprises: Providing initial high-frequency ultrasonic vibration to a crystal ingot immersed in a liquid by an ultrasonic vibrator to pre-strip the crystal ingot; The ultrasonic tool head is driven to contact the end surface of the crystal ingot and perform secondary high-frequency ultrasonic vibration to peel off a wafer from the crystal ingot.

10. The wafer separation method according to claim 9, characterized in that: The method of driving the ultrasonic tool head to contact the end surface of the ingot and perform secondary high-frequency ultrasonic vibration to peel off a wafer from the ingot comprises: Driving the ultrasonic tool head to contact and absorb the end surface of the ingot; A secondary high-frequency ultrasonic vibration is applied to the crystal ingot and an upward lifting force is applied to the crystal ingot at the same time, so as to peel a wafer from the crystal ingot.

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