Wafer and carrier disc automatic separation method

Abstract

The invention discloses a method for automatically separating a wafer from a carrier plate. The method comprises the following steps of: S1, splitting a carrier substrate which finishes a process into a circular ring with a wafer and a base; s2, automatically identifying the alignment angle of the bevel edge of the wafer and the bevel edge of the circular ring through a visual system, and judging whether jacking separation is performed or not according to an alignment angle identification result: if the alignment angle is smaller than a preset threshold value, directly jacking separation, and entering S4; if the alignment angle is greater than a preset threshold value, entering S3; s3, sucking the wafer by using a sucking disc mechanism, driving the circular ring to rotate and correct by using a rotating mechanism so that the bevel edge of the wafer is aligned with the bevel edge of the circular ring, then jacking the wafer by using a jacking mechanism so that the wafer is separated from the circular ring, and entering S4 after successful separation; and S4, the wafer is calibrated and then transferred to a wafer discharging device, the circular ring and the base are combined into a slide glass base, and wafer unloading is completed. The device has the characteristics of simple principle, convenience in operation, high safety, high separation efficiency and the like.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and more specifically to an automatic separation method for wafers and carrier disks. Background Technology

[0002] Currently, in the field of chemical vapor deposition semiconductor equipment, for horizontal gas flow reaction equipment, the wafer-supporting device typically uses a planar disk-shaped graphite substrate. For monolithic reaction equipment, such as... Figure 1 As shown, a typical silicon carbide epitaxial substrate 2 mainly consists of three parts: from bottom to top, a base 22, a ring 21, and a wafer 1. The base 22 and ring 21 are called wafer trays. All three components—base 22, ring 21, and wafer 1—are designed with beveled edges. The wafer's beveled edge must align with the ring's beveled edge to ensure proper separation of the wafer from the graphite tray. The automatic separation process of the wafer and graphite tray is complex. This is because, firstly, the front side of the wafer should not come into contact with any type of mechanism; otherwise, additional cleaning processes may be required, affecting efficiency or directly leading to fatal defects in the device. Secondly, the wafer tray rotates during the equipment process, which can easily cause relative displacement between the wafer and the substrate, resulting in misalignment and jamming between the wafer and the ring's beveled edge.

[0003] To enable automatic separation of wafers from wafer carriers, existing technologies mainly employ the following two methods: Firstly, as Figure 2 As shown, by setting up a wafer carrier base disassembly and assembly device, combined with a lifting mechanism, the wafer can be lifted and separated from the wafer carrier ring. The main drawbacks are: the wafer carrier disk rotates during the equipment process, which can easily cause relative displacement between the wafer and the base. This can cause the wafer's beveled edge to get stuck in the ring during vertical lifting. In this case, the lifting mechanism will simultaneously lift both the ring and the wafer, making it impossible to separate the wafer smoothly, requiring complete manual intervention to resolve the issue.

[0004] Second, as Figure 3 As shown, a robotic arm with suction can flexibly remove wafers without bending them by translating and lifting them at a reasonable tilt angle. The main drawbacks are: complex control flow and high precision requirements for the actuators; also, the high cost of configuring a multi-degree-of-freedom robotic arm. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an automatic wafer and carrier disk separation method that is simple in principle, convenient to operate and highly versatile, in order to overcome the shortcomings of the existing technology.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: An automated method for separating a wafer from a carrier disk includes the following steps: Step S1: Disassemble the completed wafer carrier into a ring with a wafer and a base; Step S2: Automatically identify the alignment angle between the wafer bevel and the annular bevel using the vision system, and determine whether to perform lifting and separation based on the alignment angle identification result: if the alignment angle is less than a preset threshold, directly lift and separate, and proceed to step S4; if the alignment angle is greater than the preset threshold, proceed to step S3. Step S3: Use the suction cup mechanism to hold the wafer, and the rotating mechanism to rotate and correct the ring so that the bevel of the wafer is aligned with the bevel of the ring. Then the lifting mechanism lifts the wafer so that the wafer is separated from the ring. After successful separation, proceed to step S4. Step S4: After calibrating the wafer, transfer it to the wafer unloading device, combine the ring and the base to form a wafer carrier, and complete the wafer unloading.

[0007] As a further improvement of the present invention, in step S2, a high-resolution vision camera 3 is used to acquire images of the oblique area of ​​the wafer and the ring from above.

[0008] As a further improvement of the present invention, an image recognition algorithm is used to extract the edge features of the oblique region and calculate the offset angle (θ) and horizontal displacement (Δx) of the current wafer relative to the ring; when the offset angle |θ|≤ 2° and the displacement |Δx|≤ 1 mm, it is determined that "it can be directly lifted and separated".

[0009] As a further improvement of the present invention, step S3 further includes: Step S31: The suction cup mechanism adsorbs the back side of the wafer and drives the wafer down by 1-2 mm, so that pressure is generated at the contact surface between the wafer and the ring. Step S32: While the suction cup mechanism holds the wafer in place, the rotating mechanism drives the ring to rotate back and forth in an amplitude of ±1°. After each rotation, the vision system detects the alignment of the wafer with the bevel of the ring and provides real-time feedback on the error. Step S33: Based on the image recognition results, the required rotation angle is calculated through the control algorithm, and the rotation mechanism rotates precisely until the alignment error between the wafer and the ring is less than a preset threshold.

[0010] As a further improvement of the present invention, step S3 also includes step S34: if the wafer and the ring are not successfully aligned after the first rotation, the system can automatically perform up to three cyclic corrections, and re-detect after each correction. If it fails three times in a row, an alarm is triggered and manual intervention is prompted.

[0011] As a further improvement of the present invention, step S3 also includes step S35: after the wafer and the ring are successfully aligned, the lifting mechanism is activated to vertically lift the wafer and separate the wafer from the ring.

[0012] As a further improvement of the present invention, in step S3, during the wafer lifting process, the vision system continuously monitors whether the wafer is detached from the ring. If it detects that the wafer is lifted but not detached, the lifting mechanism lowers and puts down the wafer. Then the system jumps to step S31 and re-adaptively separates.

[0013] As a further improvement of the present invention, in step S4, the wafer is translated and rotated by a calibration platform so that the wafer is in a standard transport posture.

[0014] Compared with the prior art, the advantages of the present invention are as follows: The automatic wafer-to-disk separation method of this invention significantly improves the separation success rate and system reliability by introducing a multi-modal adaptive adjustment mechanism, a dynamic friction enhancement control strategy, and a closed-loop vision-motion collaborative feedback system. Simultaneously, it reduces reliance on high-precision mechanical structures, achieving low-cost, highly compatible automatic separation. This separation method is applicable to epitaxial equipment for wide-bandgap semiconductor materials such as silicon carbide and gallium nitride, improving the separation efficiency between the substrate and the disk, thereby increasing equipment production efficiency. Attached Figure Description Figure 1 This is a schematic diagram of the slide base structure; Figure 2 This is one of the schematic diagrams of the existing process for separating wafers and wafer carrier disks; Figure 3 Branch 2 is a schematic diagram of the existing process for separating wafers and wafer carrier disks; Figure 4 This is a schematic diagram of the automatic separation process between the wafer and the carrier disk in a specific embodiment of the present invention; Figure 5 This is a schematic diagram of the structural principle of the separation system in a specific embodiment of the present invention.

[0015] Legend: 1. Wafer; 2. Carrier base; 21. Ring; 22. Base; 3. Vision camera; 4. Pick-and-place channel; 5. Support stage; 6. Suction cup mechanism; 7. Rotation mechanism. Detailed Implementation

[0016] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but this does not limit the scope of protection of the present invention.

[0017] In the description of this invention, it should be understood that the terms "side", "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0018] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more unless otherwise explicitly specified.

[0019] Example like Figure 4 and Figure 5 As shown, the automatic separation method for wafers and carrier disks of the present invention includes the following steps: Step S1: Taking a silicon carbide epitaxial device as an example, after wafer 1 has completed growth, the device enters the unloading stage. First, the wafer carrier 2 is removed from the reaction chamber by a robotic arm and sent to the separation station. The wafer carrier 2, after the process is completed, is separated into a ring 21 with wafer 1 and a base 22. The ring 21 with wafer 1 is placed on a rotatable support platform 5. The rotation mechanism 7 drives the support platform 5 to rotate, thereby causing the ring 21 to rotate. The specific structure of the support platform 5 and the rotation mechanism 7 can adopt conventional settings in the art, and will not be described in detail here.

[0020] Step S2: The alignment angle between the bevel of wafer 1 and the bevel of ring 21 is automatically identified by the vision system, and a decision is made on whether to perform lifting and separation based on the alignment angle identification result. If the alignment angle is less than a preset threshold, lifting and separation is performed directly, and the process proceeds to step S4; if the alignment angle is greater than the preset threshold, the process proceeds to step S3.

[0021] Step S3: The wafer 1 is held in place by the vertically movable suction cup mechanism 6. The rotation mechanism 7 drives the ring 21 to rotate and correct itself via the support platform 5, so that the bevel of the wafer 1 is aligned with the bevel of the ring 21. Then, the lifting mechanism lifts the wafer 1 within the pick-and-place channel 4, separating the wafer 1 from the ring 21. After successful separation, proceed to step S4. The specific structures of the suction cup mechanism 6 and the lifting mechanism can adopt conventional settings in the art, and will not be described in detail here.

[0022] Step S4: Wafer 1 is translated and rotated on the calibration platform to ensure it is in a standard transport orientation. It is then transferred to the wafer transport track by the unloading robot. The ring 21 and base 22 are combined to form the wafer carrier base 2, which is returned to the loading station for the next round of use, completing the wafer unloading process.

[0023] In this embodiment, all actions are uniformly scheduled by the PLC or embedded controller, and with the closed-loop feedback of the vision system, the entire process is automated. In step S2 of this implementation, a high-resolution vision camera 3 is used to acquire images of the inclined area of ​​wafer 1 and ring 21 from above. An image recognition algorithm is used to extract the edge features of the inclined area, and the offset angle (θ) and horizontal displacement (Δx) of wafer 1 relative to ring 21 are calculated. When the offset angle |θ| ≤ 2° and the displacement |Δx| ≤ 1 mm, it is determined that "it can be directly lifted and separated".

[0024] In step S3 of this embodiment, when the identification result is "cannot be directly separated", the following steps are performed: In step S31, the suction cup mechanism 6 adsorbs the back side of wafer 1 and lowers wafer 1 by 1-2 mm, creating slight pressure on the contact surface between wafer 1 and ring 21. This actively increases the friction between ring 21 and the support stage 5, preventing slippage during subsequent rotation. By introducing a dynamic friction enhancement control strategy, no additional clamping mechanism is needed; "passive locking" is achieved solely through the suction cup mechanism 6, significantly improving the stability and reliability of rotation adjustment.

[0025] Step S32: While the suction cup mechanism 6 holds the wafer 1 in place, the rotation mechanism 7 drives the support stage 5 and the ring 21 to rotate back and forth at a small angle with an amplitude of ±1°. After each rotation, the vision system detects the alignment of the wafer 1 with the oblique edge of the ring 21 and provides real-time feedback on the error.

[0026] Step S33: Based on the image recognition results, the required rotation angle is calculated through a control algorithm, and the rotation mechanism 7 rotates precisely until the alignment error of the oblique edge of wafer 1 and ring 21 is less than a preset threshold. This embodiment not only relies on image recognition for alignment but also combines rotation correction and visual closed-loop feedback to form a closed-loop control process of recognition, execution, detection, and correction, achieving fully automated and intelligent operation. Compared to existing technologies that rely solely on single image judgment or flexible movement of a robotic arm, this invention has stronger adaptive capabilities, especially suitable for minor offsets caused by equipment vibration or thermal deformation.

[0027] Step S34: If wafer 1 and ring 21 are not successfully aligned after the first rotation, the system can automatically perform up to three cyclic corrections, re-checking after each correction. If three consecutive attempts fail, an alarm is triggered and manual intervention is prompted. By introducing an automatic cyclic correction mechanism of up to three times, the system is allowed to make multiple fine adjustments after the first failed attempt, significantly improving the separation success rate. Simultaneously, automatic alarms and manual intervention prompts are set to prevent the system from falling into an infinite loop, balancing automation and safety.

[0028] After successful alignment of wafer 1 and ring 21 in step S35, the lifting mechanism is activated to vertically lift wafer 1, separating it from ring 21. During the lifting process, the vision system continuously monitors whether wafer 1 has detached from ring 21. If wafer 1 is detected as being lifted but not detached, the lifting mechanism descends and lowers wafer 1. The system then jumps to step S31 to re-adaptively separate, repeating the attempt a maximum of three times. If successful, proceed to step S4; otherwise, automatically pause and perform fine-tuning.

[0029] In this embodiment, the front side of the wafer avoids contact with any mechanical components throughout the entire process. Operation is performed solely by using a suction cup mechanism to hold the back side of the wafer, ensuring a clean wafer surface and consistent device performance. Simultaneously, the entire separation system requires only a suction cup mechanism, a rotation drive, and a lifting mechanism, eliminating the need for a multi-degree-of-freedom robotic arm, significantly reducing system complexity and maintenance costs. Furthermore, through parameterized settings such as offset threshold, rotation angle, and suction cup descent distance, it can flexibly adapt to silicon carbide wafers of different sizes and can also be extended to epitaxial devices for wide-bandgap semiconductor materials such as gallium nitride (GaN) and diamond, demonstrating excellent versatility and scalability.

[0030] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for automatically separating a wafer from a carrier disk, characterized in that, Includes the following steps: Step S1: The completed wafer substrate (2) is split into a ring (21) with a wafer (1) and a base (22). Step S2: Automatically identify the alignment angle between the bevel of the wafer (1) and the bevel of the ring (21) through the vision system, and determine whether to perform lifting separation based on the alignment angle identification result: if the alignment angle is less than the preset threshold, lift separation directly and proceed to step S4; if the alignment angle is greater than the preset threshold, proceed to step S3. Step S3: Use the suction cup mechanism to hold the wafer (1), and the rotation mechanism drives the ring (21) to rotate and correct so that the oblique edge of the wafer (1) is aligned with the oblique edge of the ring (21). Then the lifting mechanism lifts the wafer (1) so that the wafer (1) is separated from the ring (21). After successful separation, proceed to step S4. Step S4: After calibrating the wafer (1), transfer it to the wafer unloading device, combine the ring (21) and the base (22) into a wafer carrier base (2), and complete the wafer unloading.

2. The automatic wafer and carrier disk separation method according to claim 1, characterized in that, In step S2, a high-resolution vision camera (3) is used to acquire images of the oblique area of ​​the wafer (1) and the ring (21) from above.

3. The automatic wafer and carrier disk separation method according to claim 2, characterized in that, The edge features of the oblique region are extracted using an image recognition algorithm, and the offset angle (θ) and horizontal displacement (Δx) of the current wafer (1) relative to the ring (21) are calculated. When the offset angle |θ|≤ 2° and the displacement |Δx|≤1 mm, it is determined that "it can be directly lifted and separated".

4. The automatic wafer and carrier disk separation method according to claim 1, characterized in that, Step S3 further includes: Step S31: The suction cup mechanism (6) adsorbs the back side of the wafer (1) and drives the wafer (1) down by 1-2 mm, so that pressure is generated on the contact surface between the wafer (1) and the ring (21); Step S32: While the suction cup mechanism (6) holds the adsorbed wafer (1), the rotation mechanism (7) drives the ring (21) to rotate back and forth with an amplitude of ±1°. After each rotation, the vision system detects the alignment of the wafer (1) and the ring (21) at the bevel and provides real-time feedback on the error. Step S33: Based on the image recognition results, the required rotation angle is calculated by the control algorithm, and the rotation mechanism (7) rotates precisely until the alignment error of the oblique edge of the wafer (1) and the ring (21) is less than the preset threshold.

5. The automatic wafer and carrier disk separation method according to claim 4, characterized in that, The step S3 also includes step S34: if the wafer (1) and the ring (21) are not successfully aligned after the first rotation, the system can automatically perform up to three cyclic corrections. After each correction, the system will re-detect. If it fails three times in a row, an alarm will be triggered and manual intervention will be prompted.

6. The automatic wafer and carrier disk separation method according to claim 5, characterized in that, Step S3 also includes step S35: After the wafer (1) and the ring (21) are successfully aligned, the lifting mechanism is activated to vertically lift the wafer (1) and separate the wafer (1) from the ring (21).

7. The automatic wafer and carrier disk separation method according to claim 6, characterized in that, In step S3, during the lifting process of the wafer (1), the vision system continuously monitors whether the wafer (1) is detached from the ring (21). If the wafer (1) is detected to be lifted but not detached, the lifting mechanism descends and puts down the wafer (1). Then the system jumps to step S31 and re-adaptively separates.

8. The automatic wafer and carrier disk separation method according to any one of claims 1 to 7, characterized in that, In step S4, the wafer (1) is translated and rotated by the calibration platform so that the wafer (1) is in a standard transmission posture.

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