Stripping device

Abstract

The utility model discloses a stripping device. The stripping device is used for stripping a wafer from a crystal ingot, and comprises a bearing unit used for bearing the crystal ingot; the stripping unit and the bearing unit are arranged at an interval, and the stripping unit is used for providing vibration for the crystal ingot and stripping the wafer from the crystal ingot; the sliding unit is connected with the bearing unit and can enable the bearing unit to move towards the stripping unit in the extending direction of the sliding unit, so that the stripping unit is in contact with the crystal ingot; the force measuring unit is arranged on the side, away from the stripping unit, of the bearing unit and is in communication connection with the stripping unit, the force measuring unit is used for detecting the pressure value borne by the bearing unit, and when it is detected that the pressure value borne by the bearing unit is larger than or equal to a preset pressure standard value, the stripping unit is driven to stop stripping the crystal ingot. Through the mode, the stripping device provided by the utility model can realize complete separation of the wafer from the crystal ingot by using the stripping unit.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wafer peeling, in particular to a peeling device. BACKGROUND

[0002] The current wafer separation technology usually adopts laser to form a modified layer inside the crystal, and then applies external force to introduce stress, so that the cracks expand at the modified layer and connect with each other, and finally form a complete peeling layer. The existing wafer separation method mainly includes two methods. One method is a cold split method, which pastes a polymer film on the end face of the cut crystal bar. Due to the difference in the thermal expansion coefficient between the polymer film and the crystal material, the wafer is peeled off from the crystal bar under the shrinkage effect of the polymer film during quenching treatment. The other wafer separation method is a mechanical external force method, which fixes the end face of the crystal bar and separates the wafer from the parent body by applying longitudinal tension or transverse shear force. However, the above two wafer separation methods have certain limitations.

[0003] The cold split method in the wafer separation method has the following disadvantages: additional consumables such as polymer film and liquid nitrogen are needed, which not only increases the operation cost, but also makes the wafer separation process difficult to control, and is prone to breakage, resulting in a low yield of finished products. In addition, the mechanical external force method such as tension or shear force also has the problem of uncontrollable operation during the peeling process. The peeling process is difficult to accurately monitor, which easily leads to peeling failure or wafer breakage, thereby seriously affecting the yield of finished products.

[0004] The current wafer separation technology still has the problem that the wafer peeling process is difficult to monitor, resulting in a low wafer separation yield. CONTENT OF THE INVENTION

[0005] The present application provides a peeling device to solve the problem that the wafer peeling process is difficult to monitor, resulting in a low wafer separation yield.

[0006] To solve the above technical problems, one technical solution adopted by the present application is to provide a peeling device. The peeling device is used for peeling wafers from a crystal ingot. The peeling device comprises: a bearing unit for bearing the crystal ingot; a peeling unit spaced apart from the bearing unit and used for providing vibration to the crystal ingot and peeling wafers from the crystal ingot; a sliding unit connected with the bearing unit and capable of moving the bearing unit towards the peeling unit in the extension direction of the sliding unit, so that the peeling unit is in contact with the crystal ingot; and a force measuring unit arranged on the side of the bearing unit away from the peeling unit and in communication connection with the peeling unit. The force measuring unit is used for detecting the pressure value borne by the bearing unit. When the pressure value borne by the bearing unit is detected to be greater than or equal to a preset pressure standard value, the peeling unit is driven to stop peeling the crystal ingot.

[0007] In some embodiments, the sliding unit comprises a fixed rod extending in a direction of the bearing unit towards the stripping unit; a sleeving rod movably sleeved on the fixed rod, the sleeving rod being connected with the bearing unit for driving the bearing unit to move up and down.

[0008] In some embodiments, the stripping unit comprises a tool head comprising a working end face; wherein the ingot comprises a cutting face, and the working end face is used to fit with the end face of the ingot to transmit vibration to the cutting face of the ingot.

[0009] In some embodiments, the fitting between the working end face and the end face of the ingot is by means of adhesive bonding or vacuum adsorption.

[0010] In some embodiments, the stripping unit further comprises an ultrasonic generator and an ultrasonic transducer, the ultrasonic generator being used to drive the ultrasonic transducer to generate ultrasonic vibration, and the ultrasonic transducer being connected with the tool head and being used to make the working end face generate ultrasonic vibration.

[0011] In some embodiments, the ultrasonic transducer comprises a piezoelectric element connected with the ultrasonic generator, the ultrasonic generator being used to generate a high-frequency voltage signal and make the piezoelectric element generate mechanical vibration of the same frequency; and an amplitude transformer connected with the ultrasonic generator and the tool head, the amplitude transformer being used to amplify the amplitude of the mechanical vibration and then transmit the mechanical vibration to the tool head, so that the working end face of the tool head generates vibration.

[0012] In some embodiments, the stripping device further comprises a base provided on a side of the force measuring unit away from the bearing unit, the base being used to mount the force measuring unit, and the fixed rod being vertically fixed on the base; a mounting frame provided on a side of the stripping unit away from the bearing unit, the mounting frame being used to mount the stripping unit; and a support frame provided on the base and connected with the mounting frame.

[0013] In some embodiments, the mounting frame is provided with an adjusting member, an end of the tool head away from the bearing unit being detachably connected with the adjusting member, and the adjusting member being used to adjust the distance between the tool head and the bearing unit.

[0014] In some embodiments, the stripping device further comprises a laser processing device used to focus laser on the ingot at a preset depth position to process the ingot to form the cutting face.

[0015] The beneficial effects of the present application are: different from the prior art, the present application discloses a peeling device. By limiting the assembly relationship between the bearing unit, the peeling unit, the sliding unit and the force measuring unit; limit the vibration of the peeling unit, realize the complete separation of the wafer from the crystal ingot by using the peeling unit; and, by controlling the vibration of the crystal ingot through the peeling unit, the vibration is transmitted to the cutting surface of the crystal ingot, the cracks expand under the vibration and connect with each other, so that the cutting surface of the crystal ingot is separated to form the wafer, which avoids the problem of wafer breakage in the traditional cold cracking or mechanical stretching mode, thereby improving the yield and quality; at the same time, the high-frequency vibration makes the process of separating the wafer from the crystal ingot more accurate and efficient, which can effectively improve the machining precision and efficiency; the present scheme does not need to use consumables such as high molecular film or liquid nitrogen in the cold cracking technology, which simplifies the process, reduces material consumption and saves production cost; further, the force measuring unit is installed on the side of the bearing unit away from the peeling unit, the force measuring unit detects the pressure value of the bearing unit in the peeling process in real time to judge whether the crystal ingot has been completely peeled, through the real-time monitoring of the force measuring unit, the completion of the peeling process can be accurately monitored, the action of the peeling unit can be stopped in time, which greatly reduces the risk of damage or damage to the formed wafer, effectively improves the wafer peeling yield, further ensures the operation simplicity and reliability, and improves the overall controllability and economy of wafer peeling. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creating laborious work.

[0017] Figure 1 is an assembly schematic diagram of the peeling device provided by the present application;

[0018] Figure 2 is an effect schematic diagram of the laser focusing in the crystal ingot to form a modified layer and micro-cracks provided by the laser processing device;

[0019] Figure 3 is an effect schematic diagram of forming an overall modified layer and micro-cracks;

[0020] Figure 4 is an effect schematic diagram of the c surface of the cutting surface;

[0021] Figure 5 is an effect schematic diagram of the micro-cracks extending along the c surface as main cracks and connecting with each other;

[0022] Figure 6 is a schematic diagram of the modified layer and the micro-cracks on both sides thereof. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative work are within the scope of protection of the present application.

[0024] The terms "first", "second", "third" in the embodiments of the present application are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second", "third" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise explicitly and specifically limited. In addition, the terms "include" and "have" 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 can optionally include steps or units that are not listed, or can optionally include other steps or units inherent to the process, method, product or device.

[0025] In this document, reference to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another. As will be apparent to those of ordinary skill in the art, embodiments described herein can be combined with other embodiments.

[0026] The present application provides a stripping device 100, refer to Figure 1 , Figure 1is an assembly schematic diagram of the stripping device provided by the present application. The stripping device 100 is used for stripping wafers 2 from a crystal ingot 1, and the stripping device 100 comprises a bearing unit 10, a stripping unit 20, a sliding unit 30 and a force measuring unit 40. The bearing unit 10 is used for bearing the crystal ingot 1; the stripping unit 20 is arranged at intervals with the bearing unit 10, and is used for providing vibration to the crystal ingot 1 and stripping wafers 2 from the crystal ingot 1; the sliding unit 30 is connected with the bearing unit 10, and can move the bearing unit 10 in the extension direction of the sliding unit 30 to the stripping unit 20, so that the stripping unit 20 is in contact with the crystal ingot 1; the force measuring unit 40 is arranged on the side of the bearing unit 10 away from the stripping unit 20, and is communicatively connected with the stripping unit 20. The force measuring unit 40 is used for detecting the pressure value borne by the bearing unit 10, and drives the stripping unit 20 to stop stripping the crystal ingot 1 when the pressure value borne by the bearing unit 10 is detected to be greater than or equal to a preset pressure standard value.

[0027] Therefore, the stripping device 100 provided by the present application limits the bearing unit 10 to bear the crystal ingot 1, wherein the crystal ingot 1 is a crystal body. The stripping unit 20 is arranged at intervals with the bearing unit 10, so that the stripping unit 20 can provide vibration to the crystal ingot 1. The sliding unit 30 is connected with the bearing unit 10, so that the sliding unit 30 can drive the stripping unit 20 to move to make the stripping unit 20 in contact with the crystal ingot 1. The force measuring unit 40 is arranged on the side of the bearing unit 10 away from the stripping unit 20, and is communicatively connected with the stripping unit 20. The force measuring unit 40 is used for detecting the pressure value borne by the bearing unit 10, and feeds back and controls the stripping unit 20 to drive the stripping unit 20 to stop continuing to strip the crystal ingot 1 when the pressure value borne by the bearing unit 10 is detected to be greater than or equal to a preset pressure standard value. That is, the force measuring unit 40 is installed on the side of the bearing unit 10 away from the stripping unit 20 to monitor the pressure change in the stripping process of the crystal ingot 1 in real time. When the pressure value borne by the bearing unit 10 is detected to reach the preset pressure standard value, it indicates that the wafer 2 has been separated. If the pressure value borne by the bearing unit 10 is detected to not reach the preset pressure standard value, the stripping unit 20 continues to vibrate until the wafer 2 is completely stripped. The connection of the force measuring unit 40 with the bearing unit 10 and the stripping unit 20 forms a pressure feedback mechanism, which can accurately monitor the completion of the stripping process, can timely stop the action of the stripping unit 20, greatly reduces the risk of damage or breakage of the formed wafer 2, and effectively improves the wafer yield, that is, not only improves the controllability of the crystal ingot 1 in the stripping process, but also effectively reduces the risk of broken wafers, and ensures the complete separation of the wafer 2.

[0028] Preferably, when the crystal ingot 1 is a cylindrical crystal ingot, the diameter of the crystal ingot 1 ranges from 100 mm to 150 mm, in other words, the diameter of the crystal ingot 1 ranges from 4 inches to 6 inches, and the target thickness of a single wafer 2 ranges from 100 μm to 500 μm.

[0029] In the embodiment of the present application, the bearing unit 10 comprises a bearing table, the force measuring unit 40 comprises a pressure sensor, the pressure sensor is arranged on the side of the bearing table away from the crystal ingot 1, and the pressure sensor can be selected as a micro-pressure sensor. It should be noted that the pressure value range of the bearing unit 10 detected by the force measuring unit 40 is 0-5 kPa, so as to monitor the pressure change in the wafer 2 peeling process in real time.

[0030] Alternatively, the pressure value of the bearing unit 10 is related to the target thickness size of the wafer 2. The force measuring unit 40 can adjust the preset pressure standard value according to different types of wafers 2. Preferably, for the wafer with a single thickness of 300-500 μm, the range of the selected preset pressure standard value is 0.5-5 kPa. When the force measuring unit 40 detects that the pressure value of the bearing unit 10 is greater than or equal to the preset pressure standard value, it indicates that the wafer 2 has completed separation; if the force measuring unit 40 detects that the pressure value of the bearing unit 10 does not reach the preset pressure standard value, the peeling device 100 will continue to maintain the ultrasonic vibration and adsorption of the peeling unit 20 to the crystal ingot 1 until the wafer 2 is completely peeled off. Through the pressure feedback mechanism formed by the force measuring unit 40, the peeling unit 20, the bearing unit 10 and the sliding unit 30, the operation parameters in the peeling process can be dynamically adjusted, the controllability of the peeling process is improved, the risk of broken pieces caused by incomplete peeling or excessive vibration is reduced, the complete separation of the wafer 2 is ensured, and the peeling efficiency and yield are improved.

[0031] Further, as shown in Figure 1 The sliding unit 30 comprises a fixed rod 31 and a sleeve rod 32. The fixed rod 31 extends along the direction of the bearing unit 10 towards the peeling unit 20. The sleeve rod 32 is movably sleeved on the fixed rod 31. The sleeve rod 32 is connected with the bearing unit 10 and is used to drive the bearing unit 10 to ascend and descend. Specifically, the sleeve rod 32 is sleeved on the fixed rod 31 in a vertical sliding manner, or the sleeve rod 32 can be sleeved on the fixed rod 31 in a threaded rotating manner. The sleeve rod 32 can be connected with a motor, and the motor is used to drive the sleeve rod 32 to ascend and descend relative to the fixed rod 31. Specifically, one end of the sleeve rod 32 away from the fixed rod 31 is fixedly connected with the bearing unit 10. Preferably, the sliding unit 30 is provided with multiple groups. When the sleeve rod 32 moves relative to the fixed rod 31, the bearing unit 10 is used to drive the crystal ingot 1 carried thereby to ascend and descend, that is, the sleeve rod 32 drives the bearing unit 10 to move towards or away from the peeling unit 20, so as to adjust the distance between the bearing unit 10 and the peeling unit 20. When the bearing unit 10 carries the crystal ingot 1 on the side close to the peeling unit 20, the sleeve rod 32 moves relative to the fixed rod 31 while adjusting the distance between the crystal ingot 1 and the peeling unit 20, so as to drive the crystal ingot 1 to contact the peeling unit 20.

[0032] ​Figure 1 The stripping unit 20 comprises a tool head 21, and the tool head 21 comprises a working end face 210. The ingot 1 is formed with a cutting face 101, and the working end face 210 is used to be attached to the end face of the ingot 2 to transmit the vibration to the cutting face 101 of the ingot 2, so that the working end face 210 of the tool head 21 performs the stripping operation on the cutting face 101 of the ingot 1, and the carrying unit 10 carries the fixed ingot 1 during the stripping operation of the ingot 1. In the preferred embodiment, the attachment between the working end face 210 and the end face of the ingot 2 is by means of adhesive bonding or vacuum adsorption, so as to ensure the stable attachment effect between the end face of the ingot 1 and the working end face 210 of the tool head 21.

[0033] Continuing to refer to Figure 1 The stripping unit 20 further comprises an ultrasonic generator (not shown) and an ultrasonic transducer 22, the ultrasonic generator is used to drive the ultrasonic transducer 22 to generate ultrasonic vibration, and the ultrasonic transducer 22 is connected with the tool head 21 and is used to make the working end face 210 generate ultrasonic vibration.

[0034] Further, the ultrasonic transducer 22 comprises a piezoelectric element (not shown) and an amplitude transformer (not shown), the piezoelectric element is connected with the ultrasonic generator, the ultrasonic generator is used to generate a high-frequency voltage signal and make the piezoelectric element generate mechanical vibration of the same frequency, the mechanical vibration is periodic expansion or periodic compression, and the amplitude transformer is connected with the ultrasonic generator and the tool head 21, the amplitude transformer is used to amplify the amplitude of the mechanical vibration and then conduct the mechanical vibration to the tool head 21, so that the working end face 210 of the tool head 21 generates high-frequency vibration.

[0035] In some specific embodiments, when the ingot 1 carried by the carrying unit 10 is a silicon carbide (SiC) material, the vibration frequency of the tool head 21 ranges from 40 kHz to 100 kHz, and / or the amplitude of the tool head 21 ranges from 5 μm to 20 μm. Since the hardness and rigidity of the SiC material are relatively high, a higher vibration frequency and / or a larger amplitude are required in the parameter design during the separation of the wafer 2, so as to avoid the internal non-uniformity of the cutting face 101 due to the too low vibration frequency or too small amplitude, thereby improving the stripping effect.

[0036] Alternatively, in other specific embodiments, when the ingot 1 carried by the carrying unit 10 is a silicon material, the vibration frequency of the tool head 21 ranges from 15 kHz to 35 kHz, and / or the amplitude of the tool head 21 ranges from 1 μm to 5 μm. Since the brittleness of the Si material is relatively low, a lower amplitude and vibration frequency are suitable for the Si material, so as to avoid the damage caused by excessive stress. The vibration frequency and / or amplitude parameter design of the Si material can balance the energy transmission of the ultrasonic wave, ensure the uniformity of the modification effect inside the cutting face 101, avoid unnecessary stress concentration, and effectively improve the stripping efficiency and yield.

[0037] Therefore, the peeling device 100 realizes the separation of the ingot 1 by the tool head 21 by limiting the peeling unit 20 as the ultrasonic generator, the ultrasonic transducer 22 and the tool head 21, driving the ultrasonic transducer 22 to generate ultrasonic vibration by the ultrasonic generator, and transmitting the ultrasonic vibration to the tool head 21. The peeling device 100 can realize the efficient separation of the wafer 2 by the ultrasonic vibration generated by the peeling unit 20.

[0038] As shown in Figure 1 , the peeling device 100 further comprises a base 50, a mounting frame 60 and a support frame 70. The base 50 is used to install the force measuring unit 40 and the sliding unit 30, and the base 50 is located on the side of the force measuring unit 40 away from the bearing unit 10. The fixed rod 31 of the sliding unit 30 is vertically fixed on the base 50. The mounting frame 60 is used to install the peeling unit 20, and the mounting frame 60 is arranged on the side of the peeling unit 20 away from the bearing unit 10. Specifically, the mounting frame 60 is used to fixedly install the tool head 21, the ultrasonic generator and the ultrasonic transducer 22. In addition, the support frame 70 is arranged on the base 50 and connected with the mounting frame 60.

[0039] Further, the mounting frame 60 is provided with an adjusting member 61, and the end of the tool head 21 away from the bearing unit 10 is detachably connected with the adjusting member 61. The adjusting member 61 is used to adjust the height of the tool head 21 relative to the bearing unit 10, and the adjusting member 61 is used to adjust the distance between the working end face 210 and the cutting surface 101 of the ingot 1 carried by the bearing unit 10.

[0040] It should be noted that, as shown in Figure 1 , the support frame 70 is connected with the base 50 and the mounting frame 60 respectively to form a rack 80 as a whole. Thus, the ultrasonic generator, the ultrasonic transducer 22, the tool head 21, the sliding unit 30 and the force measuring unit 40 are fixed and supported by the rack 80 as a whole. The bearing unit 10 is connected to the rack 80 by the sliding unit 30 and supported to move, so that the bearing unit 10 is arranged in the working area below the ingot 1, and the bearing unit 10 is also used to receive the wafer 2 separated from the ingot 1. In addition, the force measuring unit 40 is arranged between the rack 80 and the bearing unit 10, so that the force measuring unit 40 can monitor and feedback the pressure of the bearing unit 10 during the peeling process of the ingot 1, thereby ensuring the stability and accuracy of the operation of separating the wafer 2 from the ingot 1.

[0041] Please refer to Figures 2-6The peeling device 100 also comprises a laser processing device (not shown) for focusing laser 90 at a preset depth position of the ingot 1 to form a cutting surface 101 on the entire surface of the ingot 1, so that the cutting surface 101 is the surface formed by the laser 90 focused at the preset depth position inside the ingot 1. The laser 90 is irradiated on the retained ingot 1 by the laser processing device to form the cutting surface 101, which is used as a peeling layer of the ingot 1 to separate the wafer 2.

[0042] Preferably, the focal depth of the laser 90 focused on the cutting surface 101 is determined according to the value of the target thickness of the wafer 2 selected; when the target thickness of the wafer 2 ranges from 100 μm to 500 μm, the focal depth of the laser 90 focused on the cutting surface 101 ranges from 100 μm to 500 μm.

[0043] Preferably, the laser processing device provides a scanning pitch value of the laser 90 ranging from 50 μm to 500 μm.

[0044] It should be noted that, as shown in Figures 2-6 , the cutting surface 101 comprises a modified layer 102 and microcracks 103. When the working end surface 210 of the tool head 21 is in contact with the cutting surface 101 of the ingot 1, the working end surface 210 can transmit ultrasonic vibration to the cutting surface 101 and connect adjacent microcracks 103 at the cutting surface 101 to form a main crack for separating the wafer 2 until the wafer 2 is peeled off at the cutting surface 101.

[0045] In addition, it should be noted that in the specific embodiment of the peeling device 100, the ingot 1 also comprises a first end surface 104, a peripheral surface 106 and a c-axis. When the ingot 1 is arranged on the carrying unit 10, the first end surface 104 is arranged on the side close to the peeling unit 20, and the second end surface, Figures 2-5 opposite to the first end surface 104 is arranged on the side away from the peeling unit 20, the c-axis is arranged opposite to the second end surface, the c-plane of the cutting surface 101 is perpendicular to the c-axis, the c-axis is arranged obliquely relative to the perpendicular line a of the first end surface 104, and the c-plane and the first end surface 104 form a deviation angle a, i.e., the c-axis and the perpendicular line a form a deviation angle a, and the deviation angle a ranges from one of 0° to 10°, 0° to 15° and 0° to 30°.

[0046] Continued from Figures 1-6 It should be noted that before the wafer 2 is separated, the ingot 1 needs to be subjected to laser modification treatment by the laser 90 irradiated by the laser processing device. The process of laser modification of the ingot 1 is as follows:

[0047] First, the crystal ingot 1 is fixed on the support unit 10 to ensure the stability of the crystal ingot 1 when the laser processing device irradiates the laser 90 to process the crystal ingot 1;

[0048] like Figure 6 As shown, when the ingot 1 is cylindrical, the diameter of the ingot 1 ranges from 100mm to 150mm, that is, the size range of the ingot 1 is 4 inches to 6 inches; and / or, the target thickness of the single wafer 2 ranges from 100μm to 500μm.

[0049] Then, a laser 90 is focused at a predetermined depth from the first end face 104 of the ingot 1 using a laser processing device to form a modified layer 102 at that depth; wherein the predetermined depth can be determined according to the target thickness of the wafer 2.

[0050] The modified layer 102 formed on the laser processing path is a strip-shaped modified layer, and microcracks 103 are generated along the c-plane due to Coulomb explosions caused by multiphoton absorption on both sides of the strip-shaped modified layer.

[0051] When the cutting surface 101 of the ingot 1 is formed, a modified layer 102 is continuously formed in a direction perpendicular to the direction in which the deviation angle α is formed, and microcracks 103 extending from the modified layer 102 along the c-plane are generated. Figure 6 As shown, the modified layer 102 is a strip-shaped modified layer located on the c-plane, and the microcracks 103 extend along the c-plane and are located on both sides of the strip-shaped modified layer.

[0052] Finally, the laser 90 completes the processing of the entire crystal ingot 1 at a certain feed rate, ensuring that the modified layer 102 is evenly distributed, providing a basis for the subsequent separation process.

[0053] After laser modification, the ingot 1 is peeled off by the peeling device 100 to generate the wafer 2. The separation process of the ingot 1 by the peeling device 100 includes:

[0054] First, the laser-modified crystal ingot 1 is fixed on the support unit 10. Then, the working end face 210 of the tool head 21 and the end face of the crystal ingot 2 are made to fit together. The end face is fitted by adhesive bonding or vacuum adsorption to ensure a stable fit between the end face of the crystal ingot 1 and the working end face 210 of the tool head 21.

[0055] The ultrasonic generator and ultrasonic transducer 22 of the stripping unit 20 start working. The ultrasonic generator drives the ultrasonic transducer 22 to generate high-frequency vibration, which transmits the vibration of the working end face 210 of the tool head 21 to the cutting surface 101 of the ingot 1. Under the action of vibration, adjacent cracks 103 on the cutting surface 101 are connected, causing the wafer 2 to separate from the ingot 1 at the modified layer 102.

[0056] wherein the separation process between the wafer 2 and the ingot 1 is described in detail with reference to Figures 2-5 .

[0057] It is to be noted that in order to ensure the stability of the ingot 1 and the wafer 2 during the separation process, the vibration frequency of the tool head 21 and the amplitude of the tool head 21 can be adjusted according to the physical properties of different crystal materials to achieve the best separation effect of the wafer 2.

[0058] When the ingot 1 carried by the carrying unit 10 is selected as a silicon carbide (SiC) material, because the hardness and rigidity of the SiC material are relatively high, a higher frequency and a larger amplitude are required during the separation process. The vibration frequency of the tool head 21 ranges from 40 kHz to 100 kHz, and / or the amplitude of the tool head 21 ranges from 5 μm to 20 μm. The design of the vibration frequency and / or the amplitude parameters can effectively ensure that the micro-cracks 103 can stably expand along the predetermined direction, i.e., the c-plane, thereby avoiding uneven expansion of the micro-cracks 103 due to too low frequency or too small amplitude, and improving the peeling effect.

[0059] When the ingot 1 carried by the carrying unit 10 is selected as a silicon (Si) material, the vibration frequency of the tool head 21 ranges from 15 kHz to 35 kHz, and / or the amplitude of the tool head 21 ranges from 1 μm to 5 μm. Because the brittleness of the Si material is relatively low, the Si material is suitable for using a lower amplitude and a vibration frequency to avoid damage caused by excessive stress. The design of the vibration frequency and / or the amplitude parameters of the Si material can balance the energy transmission of the ultrasonic wave, ensure the uniform expansion of the micro-cracks 103, and avoid unnecessary stress concentration, thereby effectively improving the peeling efficiency and the yield.

[0060] Different from the prior art, the application discloses a peeling device. By limiting the assembly relationship between the bearing unit, the peeling unit, the sliding unit and the force measuring unit, the peeling unit is caused to vibrate, the wafer is separated from the ingot by the peeling unit, the vibration of the ingot is controlled by the peeling unit, the vibration is transmitted to the cutting surface of the ingot, the cracks are connected to each other under the vibration, the cutting surface of the ingot is separated to form the wafer, the wafer breakage problem under the traditional cold cracking or mechanical stretching mode is avoided, the yield and quality are improved, the high-frequency vibration makes the process of separating the wafer from the ingot more accurate and efficient, the machining precision and efficiency are effectively improved, the high polymer film or liquid nitrogen and other consumables in the cold cracking technology are not needed, the process is simplified, the material consumption is reduced, the production cost is saved, the force measuring unit is installed on the side of the bearing unit away from the peeling unit, the pressure value borne by the bearing unit in the peeling process is detected in real time, whether the ingot has been completely peeled is judged, the completion of the peeling process is accurately monitored by the real-time monitoring of the force measuring unit, the action of the peeling unit is stopped in time, the risk of damaging or breaking the formed wafer is greatly reduced, the wafer peeling yield is effectively improved, the operation simplicity and reliability are further ensured, and the overall controllability and economy of wafer peeling are improved.

[0061] The peeling device 100 provided by the embodiments of the application is described in detail above, specific examples are applied in the application to describe the principles and implementation manners of the application, and the above embodiment descriptions are only used to help understand the technical solutions and core ideas of the application; those skilled in the art should understand that the technical solutions recorded in the above embodiments can be modified or some technical features can be replaced by equivalents; the modification or replacement does not make the essence of the corresponding technical solution deviate from the scope of the technical solutions of the embodiments of the application.

Claims

1. A stripping device for stripping wafers from a crystal ingot, characterized in that, The application relates to a wafer stripping device. The device comprises: a bearing unit for bearing the ingot; a stripping unit arranged in a spaced manner with the bearing unit, for providing vibration to the ingot and stripping wafers from the ingot; a sliding unit connected with the bearing unit and capable of moving the bearing unit towards the stripping unit in the extension direction of the sliding unit, so that the stripping unit is in contact with the ingot; 2. The peeling apparatus according to claim 1, characterized by a force measuring unit arranged on the side of the bearing unit away from the stripping unit and in communication connection with the stripping unit, the force measuring unit being used for detecting the pressure value borne by the bearing unit, and driving the stripping unit to stop stripping the ingot when the pressure value borne by the bearing unit is equal to or greater than a preset pressure standard value. The sliding unit comprises: a fixed rod arranged in the direction of the bearing unit towards the stripping unit; 3. The peeling apparatus according to claim 1, characterized by a sleeve rod movably sleeved on the fixed rod, the sleeve rod being connected with the bearing unit and used for driving the bearing unit to ascend and descend. The stripping unit comprises: a tool head comprising a working end face; 4. The peeling apparatus according to claim 3, characterized by wherein the ingot comprises a cutting surface, and the working end face is used for being in close contact with the end face of the ingot, so as to transmit vibration to the cutting surface of the ingot.

5. The peeling apparatus according to claim 3, wherein The close contact mode between the working end face of the tool head and the end face of the ingot is adhesive bonding or vacuum adsorption. The stripping unit further comprises:

6. The peeling apparatus according to claim 5, wherein an ultrasonic generator and an ultrasonic transducer, the ultrasonic generator being used for driving the ultrasonic transducer to generate ultrasonic vibration, and the ultrasonic transducer being connected with the tool head and used for making the working end face generate ultrasonic vibration. The ultrasonic transducer comprises: a piezoelectric element connected with the ultrasonic generator, the ultrasonic generator being used for generating an electric voltage signal and making the piezoelectric element generate mechanical vibration of the same frequency; 7. The peeling apparatus according to claim 2, wherein an amplitude transformer connected with the ultrasonic generator and the tool head, the amplitude transformer being used for amplifying the amplitude of mechanical vibration and then conducting the mechanical vibration to the tool head, so that the working end face of the tool head generates vibration. The stripping device further comprises: a base arranged on the side of the force measuring unit away from the bearing unit, the base being used for mounting the force measuring unit, and the fixed rod being vertically fixed on the base; a mounting rack arranged on the side of the stripping unit away from the bearing unit, the mounting rack being used for mounting the stripping unit; 8. The peeling apparatus according to claim 7, characterized by a support rack arranged on the base and connected with the mounting rack.

9. The peeling apparatus according to claim 3, wherein An adjusting member is arranged on the mounting rack, one end of the tool head away from the bearing unit is detachably connected with the adjusting member, and the adjusting member is used for adjusting the distance between the tool head and the bearing unit. The stripping device further comprises: a laser processing device used for focusing laser on a preset depth position of the ingot, so as to process the cutting surface.

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