Back scanning type debonding device

Abstract

The embodiment of the utility model discloses a back scanning type de-bonding device, which is characterized in that a laser scanning assembly is arranged below a wafer carrying plate, so that laser can sequentially pass through a carrying plate substrate and a bonding layer and is absorbed by the bonding layer, the carrying plate substrate and a device substrate are de-bonded, and the device substrate is positioned above the carrying plate substrate, so that the device substrate can be separated from the carrying plate substrate. The device substrate can be directly taken away to the next working procedure without being taken away together with the carrier substrate, the wafer does not need to be overturned, and the situation that the device substrate falls off from the carrier substrate in the carrying or wafer overturning process is effectively avoided.

Description

Technical Field

[0001] This application relates to the field of chip debonding technology, specifically to a back-scan debonding device. Background Technology

[0002] In the field of chip manufacturing, 3D heterogeneous integration technology is a key process for achieving high-integration chip manufacturing. The debonding stage plays a crucial role in pattern transfer and the advancement of the chip manufacturing process. Currently, laser debonding has become the mainstream choice for debonding processes due to its advantages in saving time and completely removing the substrate.

[0003] Traditional laser debonding processes typically employ a forward scanning method. During laser scanning, the laser breaks the bond between the bonding layer and the carrier substrate and device substrate, subsequently debonding the carrier substrate and device substrate using appropriate techniques. However, in traditional laser debonding processes, although the bond between the carrier substrate and device substrate is broken, the device substrate cannot be removed immediately. It must be transported along with the carrier substrate to subsequent processes, posing a risk of the device substrate falling off the wafer carrier and being damaged during transport. Utility Model Content

[0004] This application provides a back-scanning debonding device to improve the risk of device substrate damage after laser debonding.

[0005] In a first aspect, embodiments of this application provide a back-scanning debonding device, comprising:

[0006] Workbench;

[0007] A laser scanning component, mounted on the worktable, is used to generate laser light and scan the wafer to be debonded.

[0008] A wafer carrier disk is disposed on a worktable to support a wafer and is transparent to light. The wafer carrier disk is located at the laser output end of the laser scanning component. The wafer includes a carrier substrate, a bonding layer and a device substrate stacked in sequence.

[0009] The laser scanning component is located below the wafer carrier, so that the laser emitted by the laser scanning component passes sequentially through the carrier substrate and the bonding layer and is absorbed by the bonding layer, thereby debonding the carrier substrate from the device substrate.

[0010] In some embodiments of this application, the laser scanning assembly includes a laser generating mechanism and a galvanometer. The laser generating mechanism is used to emit and shape laser light. The galvanometer is located at the laser output end of the laser generating mechanism and below the wafer carrier, and is used to control the irradiation direction of the laser so that the laser light passing through the galvanometer can irradiate the target area of ​​the wafer.

[0011] In some embodiments of this application, the device substrate is provided with at least one partition groove to divide the device substrate into multiple device sub-substrates by the partition groove, the bonding layer includes at least two bonding sub-layers, each device sub-substrate is provided with a corresponding bonding sub-layer, the galvanometer controls the laser to pass through the carrier substrate and irradiate the bonding sub-layer to be debonded, so as to debond the device sub-substrate to be debonded and the carrier substrate.

[0012] In some embodiments of this application, a visible light positioning camera is included. The visible light positioning camera is disposed on the worktable and located above the wafer carrier, and is used to position the irradiation position of the laser emitted by the laser scanning component so that the laser can irradiate the wafer position to be debonded.

[0013] In some embodiments of this application, a first moving mechanism is included, which is disposed on the worktable and connected to the visible light positioning camera to drive the visible light positioning camera to move relative to the wafer carrier.

[0014] In some embodiments of this application, the laser generating mechanism is a pulsed laser for emitting infrared laser with a wavelength of 1064nm. The adjustable range of the laser power of the pulsed laser is 2W-15W, the adjustable range of the pulse width is 10ns-100ns, and the adjustable range of the pulse frequency is 1kHz-100kHz.

[0015] In some embodiments of this application, the wafer carrier is a quartz glass carrier, and the transmittance of the wafer carrier to the infrared laser is greater than 90%.

[0016] In some embodiments of this application, the workbench includes a base, a top platform, and a plurality of support columns, wherein the base and the top platform are disposed opposite to each other, and the support columns are disposed between the base and the top platform.

[0017] In some embodiments of this application, a second moving mechanism is included, disposed on the worktable and connected to the laser scanning assembly, to drive the laser scanning assembly to move relative to the wafer carrier.

[0018] In some embodiments of this application, an infrared observation camera is included, mounted on the second moving mechanism, for observing the laser ablation of the bonding layer.

[0019] Therefore, in this embodiment, by placing the laser scanning component below the wafer carrier, the laser can pass through the carrier substrate and the bonding layer in sequence and be absorbed by the bonding layer, thereby debonding the device substrate from the carrier substrate. Since the device substrate is located above the carrier substrate, it will not fall off due to its own gravity, and can be directly removed to the next process without removing it along with the carrier substrate or flipping the wafer. This effectively avoids the device substrate falling off the carrier substrate during handling or wafer flipping. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A three-dimensional structural schematic diagram of a back-scanning debonding device provided for an embodiment of this utility model;

[0022] Figure 2 A front view of a back-scanning debonding device provided in an embodiment of this utility model.

[0023] Figure 3 A schematic diagram of the structure of a wafer carrier in a back-scanning debonding device provided in an embodiment of this utility model;

[0024] Figure 4 This is a flowchart illustrating a back-scanning debonding method provided in an embodiment of the present invention.

[0025] Explanation of reference numerals in the attached figures:

[0026] 1. Worktable; 2. Laser scanning assembly; 21. Laser generating mechanism; 22. Galvanometer; 3. Wafer carrier; 4. Visible light positioning camera; 5. First moving mechanism; 6. Second moving mechanism; 7. Infrared observation camera; 8. Wafer; 81. Carrier substrate; 82. Bonding layer; 821. Bonding sublayer; 83. Device substrate; 831. Separator groove; 832. Device sub-substrate. Detailed Implementation

[0027] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or specifying the number of technical features indicated. Therefore, features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0029] Please see Figures 1 to 3 This application provides a back-scanning debonding device, including a stage 1, a laser scanning component 2, and a wafer carrier 3. The laser scanning component 2 is disposed on the stage 1 and is used to generate laser light and scan the wafer to be debonded. The wafer carrier 3 is disposed on the stage 1, is used to support the wafer 8, and is transparent to light. The wafer carrier 3 is located at the laser output end of the laser scanning component 2. The wafer 8 includes a carrier substrate 81, a bonding layer 82, and a device substrate 83 stacked sequentially. The laser scanning component 2 is positioned below the wafer carrier 3 so that the laser light emitted from the laser scanning component 2 passes sequentially through the carrier substrate 81 and the bonding layer 82 and is absorbed by the bonding layer 82, thereby debonding the device substrate 83 and the carrier substrate 81.

[0030] The technical solution provided in this application places the laser scanning component 2 below the wafer carrier 3, so that the laser can pass through the carrier substrate 81 and the bonding layer 82 in sequence and be absorbed by the bonding layer 82, thereby debonding the device substrate 83 from the carrier substrate 81. Since the device substrate 83 is located above the carrier substrate 81, the device substrate 83 will not fall off due to its own gravity, and the device substrate 83 can be directly removed to the next process without removing it together with the carrier substrate 81, and without flipping the wafer 8. This effectively avoids the device substrate 83 falling off the carrier substrate 81 during handling or wafer 8 flipping.

[0031] In one example, the worktable 1 is made of high-strength, high-precision aluminum alloy, with its surface flatness controlled within ±0.01mm to ensure the stability of the wafer carrier 3 and other components placed on it. The worktable 1 includes a base and a top platform, which are arranged opposite each other to allow sufficient space between them to accommodate components such as the laser scanning assembly 2. The worktable 1 also includes multiple support columns located between the base and the top platform to connect and support the top platform and the base.

[0032] In some embodiments, the laser scanning assembly 2 includes a laser generating mechanism 21 and a galvanometer 22. The laser generating mechanism 21 employs an advanced pulsed laser capable of generating infrared laser with a wavelength of 1064nm. The laser power is continuously adjustable within the range of 2W-15W, the pulse width is 10ns-100ns, and the pulse frequency is 1kHz-100kHz. This range of laser parameters can meet the debonding operations of different materials and processes. The laser generating mechanism 21 is internally equipped with a high-precision laser shaping component. Through a combination of lens groups and reflectors, the laser beam can be shaped into a circular spot with an adjustable diameter between 5μm and 50μm, ensuring uniform distribution of laser energy at a designated location and improving the debonding effect. The galvanometer 22 is mounted below the laser output end of the laser generating mechanism 21 and below the wafer carrier 3. The galvanometer 22 is driven by a high-speed, high-precision motor, with an angle control accuracy of ±0.01°, enabling rapid and accurate changes in the laser's irradiation direction, allowing the laser to irradiate the target area of ​​the wafer 8 along a preset path. The target area refers to the portion of wafer 8 that needs to be debonded. If the entire wafer 8 needs to be debonded, the target area refers to the entire end face of wafer 8. If only a portion of wafer 8 needs to be debonded, then it refers to the end face region of that portion. The wafer carrier 3 is made of quartz glass with high transmittance (greater than 90%) to 1064nm infrared light, and is 5mm thick. Its surface is finely polished, with a roughness of less than 0.05μm, ensuring that wafer 8 can fit tightly on the carrier and preventing displacement during debonding. The wafer carrier 3 is designed with a diameter of 200mm according to common wafer specifications, accommodating most wafer products on the market. Positioning slots are provided on the edge of the wafer carrier 3, which cooperate with positioning pins on the worktable 1 to achieve rapid and accurate positioning of the wafer carrier 3 on the worktable 1.

[0033] In actual operation, the wafer 8 to be debonded is first placed on the wafer carrier 3. From bottom to top, the wafer 8 consists of a carrier substrate 81, a bonding layer 82, and a device substrate 83. The laser scanning assembly 2 is located below the wafer carrier 3. The laser generating mechanism 21 is activated, and the generated laser light, after being shaped, enters the galvanometer 22. According to the debonding requirements of the wafer 8, the operator sets parameters such as laser power, pulse width, and pulse frequency through the control system, and simultaneously sets the scanning path and range of the galvanometer 22. The galvanometer 22 precisely controls the irradiation direction of the laser according to the instructions of the control system, so that the laser light passes through the carrier substrate 81 and the bonding layer 82 in sequence. The energy of the laser breaks the bonding force between the bonding layer 82 and the carrier substrate 81 and the device substrate 83, thus achieving the debonding operation. After debonding is completed, the device substrate 83 can be directly removed from above for subsequent processing steps. Compared to traditional laser debonding processes that use a forward scanning method, where the device substrate 83 is located at the bottom after debonding and is prone to falling and being damaged from the wafer carrier 3 during handling, this embodiment uses a laser that enters from below the wafer carrier 3. After debonding, the device substrate 83 is located at the top and can be directly removed from above, avoiding the risk of the device substrate 83 falling off the carrier substrate 81 during handling. In actual production, statistics from 1000 debonding operations show that the traditional process resulted in 50 instances of device substrate 83 falling and being damaged, a damage rate of 5%; while using this back-scanning debonding device, the number of instances of device substrate 83 falling and being damaged was 0, effectively solving the problem of device substrate 83 falling and being damaged and improving production yield.

[0034] Further, please see Figure 3 The device substrate 83 is provided with at least one partition groove 831 so that the device substrate 83 is divided into multiple device sub-substrates 832 by the partition groove 831. The bonding layer 82 includes at least two bonding sub-layers 821. Each device sub-substrate 832 is provided with a corresponding bonding sub-layer 821. The galvanometer 22 controls the laser to pass through the carrier substrate 81 and irradiate the bonding sub-layer 821 and the device sub-substrates 832 to be debonded, so that the device sub-substrates 832 to be debonded and the carrier substrate 81 are debonded.

[0035] For example, during the fabrication of the device substrate 83, two perpendicular partition grooves 831, each 20 μm wide and 50 μm deep, are created on the surface of the device substrate 83 using a laser, thereby dividing the device substrate 83 into four identical device sub-substrates 832. During the fabrication process, a bonding sub-layer 821 is formed for each device sub-substrate 832. The thickness of the bonding sub-layer 821 is less than 1 μm to ensure that the bonding area and bonding strength between each device sub-substrate 832 and the corresponding bonding sub-layer 821 are relatively uniform, which is beneficial for the consistency of subsequent debonding operations. The galvanometer 22 in the laser scanning assembly 2 is connected to a high-precision motor, which is controlled by a dedicated drive circuit connected to the device's control system. The control system employs an advanced motion control algorithm, which, through programming settings, can precisely control the angle change of the galvanometer 22, achieving precise control of the laser irradiation direction. It should be noted that the control of the galvanometer 22 is prior art and will not be described further here. Before the debonding operation, the operator inputs corresponding instructions into the control system based on the layout of the device sub-substrate 832 and the area to be debonded, setting the scanning path and range of the laser. For example, if it is necessary to debond two adjacent device sub-substrates 832 and their corresponding bonded sub-layers 821, the operator can specify the coordinate range of these two areas in the control system. The wafer 8 with the specific structure is placed on the wafer carrier 3, ensuring that the wafer 8 is accurately positioned. The laser generating mechanism 21 is turned on to generate a laser with a wavelength of 1064nm and a power of 15W. After being shaped, the laser enters the galvanometer 22. The control system drives the motor of the galvanometer 22 to work according to the preset instructions, causing the galvanometer 22 to swing according to the set angle and path. Under the control of the galvanometer 22, the laser passes through the carrier substrate 81 in sequence and accurately irradiates the designated bonded sub-layers 821 to be debonded.

[0036] Traditional laser debonding processes cannot perform precise localized debonding on the partitioned structure of the device substrate 83. This embodiment, however, forms multiple device sub-substrates 832 by setting partition grooves 831 on the device substrate 83, and correspondingly sets bonding sub-layers 821. Combined with precise control of the laser irradiation direction by the galvanometer 22, it can achieve precise debonding of specific device sub-substrates 832 and their bonding sub-layers 821. In actual testing, 100 wafers 8 with the same partitioned structure were selected for debonding experiments. Traditional processes can only perform overall debonding, failing to meet the requirements for debonding localized areas. This device, however, can accurately debond designated device sub-substrates 832 with a debonding accuracy of ±2μm, effectively improving the precision and flexibility of debonding and meeting the needs of differentiated processing of different regions in chip manufacturing. Because the device sub-substrate 832 can be debonded in specific areas, for wafers 8 with local defects, it is not necessary to scrap the entire wafer 8. Only the device sub-substrate 832 corresponding to the defective area needs to be debonded and replaced, which greatly reduces production costs. Furthermore, by using a local debonding method, and with the device substrate 83 positioned above the carrier substrate 81 and the laser scanning component 2 located below the carrier substrate 81, the locally debonded device sub-substrate 832 will not fall off during debonding. Instead, after debonding, the device sub-substrate 832 can be directly transferred to the next process.

[0037] In some embodiments, see Figure 1 and Figure 2 The back-scanning debonding device includes a visible light positioning camera 4. The visible light positioning camera 4 is located on the worktable 1 and above the wafer carrier 3, and is used to position the irradiation position of the laser emitted by the laser scanning assembly 2 so that the laser can irradiate the position of the wafer 8 to be debonded.

[0038] For example, the visible light positioning camera 4 is a high-resolution industrial camera with over 5 million pixels and a telecentric lens, which effectively reduces image distortion caused by viewing angle issues and ensures positioning accuracy. The lens of the visible light positioning camera 4 is vertically downward and aligned with the wafer carrier 3. Before performing the debonding operation, the wafer 8 to be debonded is placed on the wafer carrier 3. The wafer 8 includes a carrier substrate 81, a bonding layer 82, and a device substrate 83 stacked sequentially. The visible light positioning camera 4 starts working and first acquires an image of the surface of the device substrate 83 on the wafer 8. Since the device substrate 83 has a pre-designed groove structure, namely the separation groove 831 described in the previous embodiment, the accurate position to be irradiated by the laser scanning component 2 is calculated by analyzing the deviation of the separation groove 831 from the preset standard position in the image. Then, the control system sends a command to the laser scanning component 2 to guide the laser to irradiate the position of the wafer 8 to be debonded. The analysis, calculation, and control processes here are all implemented by a computer.

[0039] Traditional laser debonding processes use an infrared camera to observe the pattern through the substrate 81 for positioning. Due to the characteristics of infrared light and the attenuation effect of the substrate 81, the image resolution and clarity are poor. This embodiment uses a visible light positioning camera 4 to directly position the device substrate 83 surface, improving positioning accuracy and reducing debonding errors caused by positioning mistakes. Traditional positioning methods are greatly affected by the material, thickness, and surface condition of the substrate 81, resulting in unstable positioning effects for different types of wafers 8. This visible light positioning camera 4, however, acts directly on the surface of the device substrate 83, unaffected by substrate 81 factors. Stable and high-precision positioning can be achieved regardless of whether the substrate 81 is made of glass or silicone grease, or regardless of its thickness.

[0040] In some embodiments, the back-scanning debonding device further includes a first moving mechanism 5. The first moving mechanism 5 is mounted on the worktable 1 and connected to the visible light positioning camera 4 to drive the visible light positioning camera 4 to move relative to the wafer carrier 3. The first moving mechanism 5 is mounted on the worktable 1 and mainly consists of an X-axis moving component, a Y-axis moving component, and a Z-axis moving component. These components cooperate to achieve precise movement of the visible light positioning camera 4 in three-dimensional space. The X-axis moving component includes a high-precision linear slide rail, which is fixed to the horizontal surface of the worktable 1, with a straightness error controlled within ±0.02 mm per meter. A slider is mounted on the slide rail and connected to the bottom of the Y-axis moving component. The X-axis drive device uses a high-precision ball screw pair, powered by a stepper motor with a step angle of 0.72°. Combined with a microstepping driver, it can achieve a displacement accuracy of ±0.01 mm in the X-axis direction.

[0041] The Y-axis moving component is mounted on the X-axis slider, and its structure is similar to that of the X-axis moving component, also employing a high-precision linear guide rail and ball screw pair. The Y-axis linear guide rail is mounted perpendicular to the X-axis guide rail, ensuring high precision and stability of Y-axis movement. The Y-axis drive motor is also a stepper motor, and through precise control of the motor's rotation, the displacement accuracy in the Y-axis direction can reach ±0.01mm.

[0042] The Z-axis movement assembly is mounted on the Y-axis slider and is used to move the visible light positioning camera 4 in the vertical direction. The Z-axis movement assembly uses a high-precision electric lifting platform, whose lead screw and nut assembly is connected to the Y-axis slider. The electric lifting platform is driven by a DC motor, and a precision reduction mechanism converts the motor's rotational motion into the linear motion of the lead screw, achieving displacement in the Z-axis direction. The displacement accuracy in the Z-axis direction can reach ±0.02mm, which can meet the camera height adjustment requirements of wafers with different thicknesses.

[0043] The visible light positioning camera 4 is connected to the top of the Z-axis moving assembly via a camera mounting bracket. The camera mounting bracket is made of high-strength aluminum alloy and precision-machined to ensure the camera's robustness and stability. The mounting bracket and the Z-axis moving assembly are connected by bolts, and a fine-tuning mechanism is provided at the connection point. The fine-tuning mechanism includes an adjusting bolt and elastic shims. By rotating the adjusting bolt, the horizontal and vertical angles of the camera can be finely adjusted with an accuracy of ±0.1°, ensuring that the camera lens is always vertically aligned with the wafer on the wafer carrier 3.

[0044] In traditional laser debonding processes, the positioning camera and laser output end are on the same side. Since positioning requires observing the pattern through the substrate 81, an infrared camera is used. However, the positioning accuracy is low and is severely affected by the thickness and material of the substrate 81. In this embodiment, the first moving mechanism 5 can precisely move along the X and Y axes, in conjunction with a high-definition visible light camera to accurately position the groove lines, providing coordinate information for the second moving mechanism 6. This achieves high-precision positioning that is unaffected by the material and thickness of the substrate 81.

[0045] In some embodiments, the back-scanning debonding apparatus further includes a second moving mechanism 6 and an infrared observation camera 7. The second moving mechanism 6 is disposed on the stage 1 and connected to the laser scanning assembly 2 to drive the laser scanning assembly 2 to move relative to the wafer carrier 3. The infrared observation camera 7 is disposed on the second moving mechanism 6 for observing the laser ablation of the bonding layer 82.

[0046] The second moving mechanism 6 is used to achieve precise displacement of the laser scanning component 2, and consists of X-axis, Y-axis, and Z-axis motion units installed perpendicularly to each other. Each axis motion unit adopts a combination structure of high-precision linear guide rails and ball screws. The structure of the second moving mechanism 6 is the same as that of the first moving mechanism 5, except that the installation position is different, which will not be described in detail here. In traditional laser debonding processes, due to the lack of precise movement control of the laser scanning component 2, the deviation of the laser irradiation position is large, resulting in poor debonding effect and even damage to the device. In this embodiment, the second moving mechanism 6 can control the positioning deviation between the laser scanning component 2 and the first moving mechanism 5 within ±0.002mm. The three-dimensional motion capability of the second moving mechanism 6 allows the laser scanning component 2 to adapt to wafers of different sizes, shapes, and substrate thicknesses 81. When processing wafers of different specifications, traditional processes usually require changing tooling fixtures or manually adjusting the equipment, which is cumbersome and time-consuming. However, the second moving mechanism 6 of this device can quickly adjust the position of the laser scanning component 2 according to the instructions of the control system without changing the tooling. For example, when switching from processing 200mm diameter wafers to 300mm diameter wafers, the traditional process requires an average adjustment time of 30 minutes. However, this device, through the automatic adjustment of the first moving mechanism 5 and the second moving mechanism 6, can complete the switch in just 3 minutes, significantly improving production efficiency and process flexibility. The infrared observation camera 7, working in conjunction with the second moving mechanism 6 and the laser scanning component 2, enables real-time monitoring of the laser ablation of the bonding layer 82. Specifically, the infrared camera mounted on the second moving mechanism 6 allows direct observation of the wafer ablation process, providing a clear and intuitive record of the process effects, which is beneficial for exploring new structures.

[0047] Please see Figure 4 The embodiments of this application also provide a back-scan debonding method, including:

[0048] S1. Place the wafer to be debonded on a wafer carrier. The wafer to be debonded includes a carrier substrate, a bonding layer and a device substrate stacked sequentially from bottom to top.

[0049] Before performing the back-scan debonding operation, the staff first cleans the wafer carrier 3 to ensure its surface is free of dust, impurities, and other contaminants, preventing these foreign objects from affecting the flatness of the wafer placement and the subsequent debonding effect. Then, the wafer to be debonded is carefully placed on the wafer carrier 3. From bottom to top, the wafer consists of a substrate 81, a bonding layer 82, and a device substrate 83. During placement, the center of the wafer must be aligned with the center of the wafer carrier 3. Precise positioning is achieved by using pre-set positioning grooves or marks on the wafer carrier 3 in conjunction with positioning features on the wafer edge. The staff uses a high-precision microscope or optical positioning equipment to check and fine-tune the wafer placement position, ensuring the wafer placement error is within ±0.05mm.

[0050] S2. The wafer to be debonded is irradiated with a laser. The laser irradiation path passes through the substrate and the bonding layer in sequence and is absorbed by the bonding layer.

[0051] The control system of the activation device is used to set the laser irradiation parameters. Based on factors such as the material properties of the wafer, the type and thickness of the bonding layer 82, a suitable laser wavelength, power, pulse width, and pulse frequency are determined. For example, for a wafer using a specific inorganic bonding layer 82, based on prior experiments and process experience, the laser wavelength is set to 1064 nm, the power adjusted to 3 W, the pulse width to 20 ns, and the pulse frequency to 50 kHz. After setting, the control system controls the second moving mechanism 6 to move the laser scanning component 2 to the initial working position, while simultaneously adjusting the position of the visible light positioning camera 4 so that it can clearly capture the surface of the device substrate 83 on the wafer for subsequent positioning operations.

[0052] After confirming the correct positions of the laser scanning assembly 2 and the visible light positioning camera 4, the visible light positioning camera 4 is used to locate the initial position by marking, and then the area to be scanned is drawn according to the software. The laser generating mechanism 21 is activated. The laser beam generated by the laser generating mechanism 21 enters the galvanometer 22 after being shaped and collimated. The control system uses a built-in image recognition algorithm to calculate the target position to be irradiated by the laser based on the preset positioning marks or features on the device substrate 83, and sends a control signal to the galvanometer 22. According to the received signal, the galvanometer 22 quickly and accurately adjusts the irradiation direction of the laser beam, so that the laser passes through the transparent wafer carrier 3, the carrier substrate 81, and the bonding layer 82 in sequence. Under the action of laser energy, the chemical bonds between the bonding layer 82 and the carrier substrate 81 or the device substrate 83 are broken, achieving debonding. After the laser generating mechanism 21 finishes scanning, the infrared observation camera 7 observes the laser ablation of the bonding layer 82 and feeds the image back to the control system. Based on the feedback images, the control system quickly assesses the quality of the current process and adjusts parameters such as laser power and pulse frequency in real time to ensure the stability and consistency of the debonding process.

[0053] S3. Remove the device substrate that has been debonded.

[0054] After laser irradiation and debonding are completed, the robotic arm or other picking device above is lowered to the wafer under the control of the control system. The end of the robotic arm is equipped with a specially designed vacuum adsorption device or gripping tool, which can stably grasp or adsorb the device substrate 83 without damaging it. Operators use the control system to operate the robotic arm to remove the debonded device substrate 83 from the wafer carrier 3 and place it in a designated collection container or subsequent processing equipment for packaging, testing, and other processes. The carrier substrate does not need to be removed and will not affect the removal of the device substrate 83.

[0055] In traditional forward-scanning laser debonding processes, the device substrate 83 is located at the bottom after debonding, making it highly susceptible to falling and being damaged from the wafer carrier 3 during transport. Statistics show that the damage rate of the device substrate 83 due to falling during conventional processes is approximately 5%. However, in this back-scanning debonding method, the device substrate 83 is located at the top after debonding and can be directly removed. Statistical analysis of 1000 debonding operations using this method showed zero instances of the device substrate 83 falling and being damaged, fundamentally solving the problem of substrate damage during transport and effectively improving wafer utilization and production yield.

[0056] This method employs precise positioning and automated control technology. Before laser irradiation, the visible light positioning camera 4 and the control system can quickly and accurately determine the irradiation position, significantly shortening the positioning time compared to traditional processes that rely on manual or low-precision positioning methods. Simultaneously, after laser irradiation, the infrared observation camera 7 can observe the ablation of the bonding layer 82, allowing for a preliminary assessment of the process quality. This facilitates further adjustments to the laser parameters by the control system based on the current process quality.

[0057] Furthermore, prior to the step of laser irradiating the wafer to be debonded, wherein the laser irradiation path sequentially passes through the carrier substrate 81 and the bonding layer 82 and is absorbed by the bonding layer 82, the method further includes:

[0058] At least one partition groove 831 is formed on the device substrate 83 to divide the device substrate 83 into at least two device sub-substrates 832, and the bonding layer 82 is divided into at least two bonding sub-layers 821. The device sub-substrates 832 and the bonding sub-layers 821 are arranged in a one-to-one correspondence.

[0059] The position of the sub-substrate 832 of the device to be unbonded is located using a visible light positioning camera 4;

[0060] The laser scanning component 2 is controlled to scan the position located by the visible light positioning camera 4, thereby completing the debonding of the target position of the wafer to be debonded.

[0061] Before placing the wafer to be debonded onto the wafer carrier 3, the device substrate 83 needs to be pre-processed. Specifically, the device substrate 83 is cut using a laser, and then the cut device substrate 83 is bonded to the carrier substrate 81. At this time, the cut-through position of the device substrate 83 and the contact surface between the carrier substrate 81 and the device substrate 83 form a separation groove 831. Correspondingly, the bonding layer 82 located between the device substrate 83 and the carrier substrate 81 is also divided into multiple bonding sub-layers 821, with each device sub-substrate 832 corresponding to one bonding sub-layer 821.

[0062] The pre-processed wafer is placed on the wafer carrier 3 and fixed in position. The visible light positioning camera 4 is activated; this camera is mounted above the worktable 1 and directly above the wafer carrier 3. The camera uses a high-resolution CMOS image sensor with 8 megapixels and a wide-angle lens, enabling it to acquire a clear image of the entire wafer surface. The visible light positioning camera 4 can magnify the image and then perform collimation on the magnified image, ensuring the collimator can locate the dividing slot 831, thereby providing position information for the second moving mechanism 6.

[0063] The control system sends a command to the laser scanning assembly 2 based on the position of the sub-substrate 832 of the bonding device to be debonded, determined by the visible light positioning camera 4. The laser generating mechanism 21 in the laser scanning assembly 2 generates a laser beam with a wavelength of 1064 nm and a maximum power of 15 W. After shaping, the laser beam enters the galvanometer 22. According to the command from the control system, the galvanometer 22 quickly and precisely adjusts the irradiation direction of the laser beam, allowing the laser to pass sequentially through the carrier substrate 81 and the bonding sub-layer 821 and be absorbed by the bonding sub-layer 821. After laser irradiation, the infrared observation camera 7 can observe the ablation of the bonding layer 82 to make a preliminary judgment on the process quality. This allows the control system to further adjust the relevant laser parameters based on the process quality.

[0064] Traditional laser debonding processes struggle to precisely debond localized areas of the device substrate 83, resulting in poor debonding performance for substrates 83 with partitioned structures. This embodiment addresses this by creating partition grooves 831 on the device substrate 83 to form multiple device sub-substrates 832, and using a visible light positioning camera 4 to precisely locate the sub-substrates 832 to be debonded, achieving precise debonding of specific areas. In a debonding experiment on 100 wafers with partition grooves 831 on the device substrate 83, traditional processes failed to accurately debond specific device sub-substrates 832, while this method can precisely debond selected device sub-substrates 832 with a debonding accuracy of ±2μm, effectively solving the problem of traditional processes' inability to precisely debond localized areas.

[0065] For example, in chip manufacturing, some wafers may only have problems in localized areas. Traditional processes can only debond and process the entire wafer, resulting in the waste of a large amount of undamaged areas. This method can operate on the device sub-substrate 832 that needs to be debonded locally. For wafers with localized defects, only the device sub-substrate 832 corresponding to the defective area needs to be debonded and repaired, without scrapping the entire wafer. Taking a chip manufacturing company as an example, before adopting this method, the wafer scrap rate due to localized defects was 12%. After adopting this method, through localized debonding and replacement, the wafer scrap rate was reduced to below 4%, greatly reducing production costs.

[0066] In some embodiments, the step of laser irradiating the wafer to be debonded, wherein the laser irradiation path sequentially passes through the carrier substrate 81 and the bonding layer 82 and is absorbed by the bonding layer 82, includes:

[0067] Drive the first moving mechanism 5 and the second moving mechanism 6 to move the laser scanning component 2 connected to the first moving mechanism 5 and the visible light positioning component connected to the second moving mechanism 6 to the target position;

[0068] When the laser scanning component 2 is turned on, the laser sequentially passes through the transparent wafer carrier, carrier substrate 81, bonding layer 82 and device substrate 83, so that the carrier substrate 81 and device substrate 83 are debonded to the bonding layer 82 respectively.

[0069] Before commencing the debonding operation, the operator inputs relevant parameters such as the dimensions of the wafer to be debonded and the location of the debonding area through the device's human-machine interface. Based on these parameters, the control system calculates the target position coordinates that the laser scanning component 2 and the visible light positioning component need to move to. The first moving mechanism 5 and the second moving mechanism 6 are composed of motion units along the X, Y, and Z axes, respectively. Each axis motion unit uses high-precision linear guides and ball screw drives, and is driven by a servo motor. Taking the X-axis motion unit of the first moving mechanism 5 as an example, after receiving pulse signals from the control system, the servo motor rotates precisely according to the number and frequency of pulses. The ball screw converts the rotational motion into linear motion, driving the connected visible light positioning component to move in the X-axis direction. The high-precision encoder in the motion unit provides real-time feedback of the motor's rotational position information to the control system, forming a closed-loop control to ensure movement accuracy. Through a similar principle, the first moving mechanism 5 and the second moving mechanism 6 work together to quickly and accurately move the laser scanning component 2 and the visible light positioning component to the target position.

[0070] Once the laser scanning component 2 and the visible light positioning component reach the target position, the laser generating mechanism 21 of the laser scanning component 2 is activated. The laser generating mechanism 21 generates an infrared laser with a wavelength of 1064nm, the power of which can be adjusted from 2W to 15W depending on the characteristics of the wafer material and the bonding layer 82. The laser beam first passes through a laser shaping component, which consists of a series of lenses and mirrors, shaping the laser beam into a circular spot with a diameter of 10μm-50μm, ensuring uniform distribution of laser energy on the bonding layer 82. The shaped laser beam then enters the galvanometer 22, which precisely controls the scanning path and angle of the laser beam according to instructions from the control system. During the laser scanning process, the visible light positioning component continuously acquires images of the wafer surface and transmits the images back to the control system. The control system uses an image recognition algorithm to monitor the alignment of the laser beam with the area to be debonded in real time. If a deviation is detected, the angle of the galvanometer 22 is adjusted promptly to ensure that the laser accurately illuminates the target area. Simultaneously, the infrared observation camera 7 monitors the laser ablation of the bonding layer 82 in real time and feeds back the acquired images to the control system. Based on the feedback from the infrared observation camera 7, the control system adjusts parameters such as laser power and pulse frequency in real time. For example, if the ablation rate of the bonding layer 82 is detected to be too fast or too slow, the control system automatically reduces or increases the laser power to ensure the stability and effectiveness of the debonding process. The laser sequentially passes through the transparent wafer carrier 3, the substrate 81, and the bonding layer 82. The laser is absorbed by the bonding layer 82, causing the substrate 81 and the device substrate 83 to debond. After debonding is complete, the control system stops the laser scanning assembly 2, completing one debonding operation.

[0071] Traditional laser debonding processes suffer from poor positioning accuracy and large laser irradiation position deviations, leading to unstable debonding results. For example, the positioning error of traditional processes is typically above ±0.5mm, while this embodiment improves the positioning accuracy to within ±0.05mm through precise movement of the first moving mechanism 5 and the second moving mechanism 6, combined with real-time monitoring and feedback from the visible light positioning component. In a statistical analysis of 100 debonding operations, the traditional process resulted in incomplete or excessive debonding due to positioning deviations 30 times, while this method resulted in only 5 such instances, significantly improving the accuracy and stability of debonding. Traditional processes, due to positioning deviations and poor laser parameter control, are prone to causing unnecessary damage to the device substrate 83, resulting in low product yield. Wafers debonded using this method, after electrical performance testing, show a yield rate exceeding 95%, up from 80% with the traditional process.

[0072] The basic concepts have been described above. Obviously, for those skilled in the art, the detailed disclosure above is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application, and therefore remain within the spirit and scope of the exemplary embodiments of this application.

[0073] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic associated with at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0074] Similarly, it should be noted that, in order to simplify the description of the present application and thus aid in the understanding of one or more embodiments, the foregoing description of the embodiments of the present application sometimes combines multiple features into a single embodiment, drawing, or description thereof. However, this disclosure method does not imply that the subject matter of the present application requires more features than those mentioned in the claims. In fact, the embodiments contain fewer features than all the features of the single embodiments disclosed above.

[0075] For each patent, patent application, patent application publication, and other material such as articles, books, specifications, publications, and documents referenced in this application, the entire contents of that patent application are incorporated herein by reference, except for historical application documents that are inconsistent with or conflict with the content of this application, and documents that limit the broadest scope of the claims of this application (currently or subsequently appended to this application). It should be noted that if there are any inconsistencies or conflicts between the descriptions, definitions, and / or terminology used in the supplementary materials of this application and the content of this application, the descriptions, definitions, and / or terminology used in this application shall prevail.

[0076] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A back-scanning debonding device, characterized in that, include: Workbench; A laser scanning component, mounted on the worktable, is used to generate laser light and scan the wafer to be debonded. A wafer carrier disk is disposed on a worktable to support a wafer and is transparent to light. The wafer carrier disk is located at the laser output end of the laser scanning component. The wafer includes a carrier substrate, a bonding layer and a device substrate stacked in sequence. The laser scanning component is located below the wafer carrier, so that the laser emitted by the laser scanning component passes sequentially through the carrier substrate and the bonding layer and is absorbed by the bonding layer, thereby debonding the carrier substrate from the device substrate.

2. The back-scanning debonding device according to claim 1, characterized in that, The laser scanning assembly includes a laser generating mechanism and a galvanometer. The laser generating mechanism is used to emit and shape the laser. The galvanometer is located at the laser output end of the laser generating mechanism and below the wafer carrier. It is used to control the irradiation direction of the laser so that the laser passing through the galvanometer can irradiate the target area of ​​the wafer.

3. The back-scanning debonding device according to claim 2, characterized in that, The device substrate is provided with at least one partition groove to divide the device substrate into multiple device sub-substrates. The bonding layer includes at least two bonding sub-layers. Each device sub-substrate is provided with a corresponding bonding sub-layer. The galvanometer controls the laser to pass through the carrier substrate and irradiate the bonding sub-layer to be debonded, so as to debond the device sub-substrate to be debonded and the carrier substrate.

4. The back-scanning debonding device according to claim 3, characterized in that, The system includes a visible light positioning camera, which is mounted on the worktable and located above the wafer carrier. The camera is used to position the laser emitted by the laser scanning assembly so that the laser can illuminate the wafer to be debonded.

5. The back-scanning debonding device according to claim 4, characterized in that, It includes a first moving mechanism, which is located on the worktable and connected to the visible light positioning camera to drive the visible light positioning camera to move relative to the wafer carrier.

6. The back-scanning debonding device according to claim 2, characterized in that, The laser generating mechanism is a pulsed laser for emitting infrared laser with a wavelength of 1064nm. The adjustable range of the laser power of the pulsed laser is 2W-15W, the adjustable range of the pulse width is 10ns-100ns, and the adjustable range of the pulse frequency is 1kHz-100kHz.

7. The back-scanning debonding device according to claim 6, characterized in that, The wafer carrier is a quartz glass carrier, and the transmittance of the wafer carrier to the infrared laser is greater than 90%.

8. The back-scanning debonding device according to claim 1, characterized in that, The workbench includes a base, a top platform, and multiple support columns. The base and the top platform are arranged opposite to each other, and the support columns are located between the base and the top platform.

9. The back-scanning debonding apparatus according to any one of claims 1 to 8, characterized in that, It includes a second moving mechanism, which is located on the worktable and connected to the laser scanning assembly to drive the laser scanning assembly to move relative to the wafer carrier.

10. The back-scanning debonding device according to claim 9, characterized in that, It includes an infrared observation camera, which is mounted on the second moving mechanism, for observing the laser ablation of the bonding layer.

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