Wafer loading and unloading apparatus, wafer loading and unloading method, and wafer transfer system
Patent Information
- Application Number
- CN202510320453.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-18
- Publication Date
- 2026-09-22
AI Technical Summary
[0004]传统的晶圆装卸载设备在机械手传片之前会扫描晶圆盒，获取晶圆盒中的槽位状态，而在机械手的传片过程中不能实时监测槽位状态，这就导致当主机要读取槽位状态信息时，晶圆装卸载设备会上传之前的扫描结果，导致主机所接收到的槽位状态信息不准确，从而容易导致故障的发生
[0040]在本公开实施例中，可以利用测距传感器在第一检测位置进行距离检测，根据测距传感器在第一检测位置所检测到的距离，判断机械手是否进出晶圆盒，并在判断出机械手进出晶圆盒的情况下，根据测距传感器检测到的距离确定机械手的取放片信息，从而可以在机械手的传片过程中，对槽位状态实时监控，有效减少或避免发生机械手撞片的风险，提高设备的安全性。
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Figure CN122803651A_ABST
Abstract
Description
Technical Field
[0001] This disclosure belongs to the field of semiconductor process technology, and specifically relates to a wafer loading and unloading device, a wafer loading and unloading method, and a wafer transport system. Background Technology
[0002] In the semiconductor manufacturing industry, wafer loadports serve as input / output ports for silicon wafer production and are widely used. These loadports are primarily installed on the front-end module (EFEM) and are suitable for loading and unloading 12-inch wafer pods (Foups) in atmospheric environments.
[0003] Before processing, wafers need to be loaded into wafer cassettes and then placed on wafer loading and unloading equipment. Finally, a robotic arm is used to transfer the wafers to the processing area for processing. After processing is completed, the wafers are transferred in reverse to be loaded into wafer cassettes.
[0004] Traditional wafer loading and unloading equipment scans the wafer cassette before the robotic arm transfers wafers to obtain the slot status. However, the slot status cannot be monitored in real time during the robotic arm's transfer process. This means that when the host computer needs to read the slot status information, the wafer loading and unloading equipment will upload the previous scan results, resulting in inaccurate slot status information received by the host computer, which can easily lead to malfunctions. Summary of the Invention
[0005] To address the aforementioned technical problems, this disclosure provides a wafer loading / unloading device, a wafer loading / unloading method, and a wafer transport system.
[0006] In a first aspect, this disclosure provides a wafer loading and unloading apparatus, comprising:
[0007] A support platform for supporting a wafer cassette, the wafer cassette having multiple slots for storing wafers;
[0008] A ranging sensor is configured to detect distance at least at a first detection position, the first detection position being located above the support platform, and the distance between the first detection position and the support platform being greater than the maximum distance from the wafer cassette's entrance / exit to the support platform; the measuring end of the ranging sensor faces the support platform; wherein, when the robot arm is not entering or exiting the wafer cassette, the distance detected by the ranging sensor at the first detection position is a first initial value; when the robot arm enters or exits the wafer cassette, the distance detected by the ranging sensor is less than the first initial value;
[0009] The controller is configured to determine whether the robotic arm has entered or exited the wafer cassette based on the distance detected by the ranging sensor at the first detection position, and, if it is determined that the robotic arm has entered or exited the wafer cassette, to determine the wafer pick-up and placement information of the robotic arm based on the distance detected by the ranging sensor at the first detection position.
[0010] In some embodiments, the wafer loading and unloading apparatus further includes a driver for driving the ranging sensor to move, the driver including: a body and a drive shaft connected to the body, the drive shaft being connected to the ranging sensor; the drive shaft is used to drive the ranging sensor to move between the first detection position and the second detection position.
[0011] In some embodiments, the orthographic projection of the second detection position on the reference plane is located between the orthographic projection of the first detection position on the reference plane and the orthographic projection of the wafer cassette on the reference plane, wherein the reference plane is the plane on which the support stage is located.
[0012] In some embodiments, the wafer loading and unloading equipment further includes a protective cover that covers the outside of the ranging sensor and the drive shaft.
[0013] In some embodiments, the controller is further configured to determine whether the wafer has slid out of the wafer cassette; the wafer loading and unloading device further includes:
[0014] The scanning mechanism is configured to scan the inside of the wafer cassette to obtain slot status information in the wafer cassette when the controller determines that the wafer has not slid out of the wafer cassette.
[0015] Secondly, this disclosure provides a wafer loading and unloading method, including:
[0016] The distance detected by the ranging sensor at a first detection position is obtained; wherein the first detection position is located above a support platform, the support platform is used to support a wafer cassette, the wafer cassette has multiple slots for storing wafers, and the distance between the first detection position and the support platform is greater than the maximum distance from the wafer cassette's entrance / exit to the support platform; the measuring end of the ranging sensor faces the support platform; wherein, when the robot arm is not entering or exiting the wafer cassette, the distance detected by the ranging sensor at the first detection position is a first initial value; when the robot arm enters or exits the wafer cassette, the distance detected by the ranging sensor is less than the first initial value;
[0017] Based on the distance detected by the ranging sensor at the first detection position, it is determined whether the robotic arm enters or exits the wafer cassette;
[0018] When it is determined that the robotic arm is entering or leaving the wafer cassette, the wafer picking and placing information of the robotic arm is determined based on the distance detected by the distance measuring sensor at the first detection position.
[0019] In some embodiments, the ranging sensor is configured to perform distance detection in real time at least at the first detection location;
[0020] The step of determining whether the robotic arm has entered or exited the wafer cassette based on the distance detected by the ranging sensor at the first detection position specifically includes:
[0021] The distance detected by the ranging sensor is sampled at preset time intervals;
[0022] The robotic arm is used to determine whether it enters or exits the wafer cassette based on the sampling distance.
[0023] In some embodiments, the step of determining the wafer pick-up and placement information of the robotic arm based on the distance detected by the ranging sensor at the first detection position when it is determined that the robotic arm has entered or exited the wafer cassette specifically includes:
[0024] Based on the relationship between sampling distance and sampling time, it can be determined whether the robotic arm is performing a wafer picking operation or a wafer placement operation;
[0025] The sampling distance determines the corresponding slot in the wafer cassette for the wafer picked up or placed by the robotic arm.
[0026] In some embodiments, the relationship between the sampling distance and the sampling time satisfies a linear equation;
[0027] The step of determining whether the robotic arm is performing a wafer picking or placing operation based on the relationship between sampling distance and sampling time specifically includes:
[0028] The sign of the slope in the linear equation is determined. When the slope is negative, the robot arm is determined to perform a wafer picking operation; when the slope is positive, the robot arm is determined to perform a wafer placement operation.
[0029] In some embodiments, the step of determining the slot in the wafer cassette corresponding to the wafer picked up and placed by the robotic arm based on the sampling distance specifically includes:
[0030] When it is determined that the robotic arm is performing a wafer picking operation, the slot in the wafer cassette corresponding to the wafer picked up by the robotic arm is determined based on the last sampling distance during the wafer picking process.
[0031] When it is determined that the robotic arm is performing a wafer placement operation, the slot in the wafer cassette corresponding to the wafer placed by the robotic arm is determined based on the first sampling distance during the wafer placement process.
[0032] In some embodiments, the wafer loading and unloading method further includes:
[0033] When the ranging sensor at the first detection position detects the first initial value for a time exceeding a preset duration, a first alarm signal is generated.
[0034] In some embodiments, prior to the step of obtaining the distance detected by the ranging sensor at the first detection position, the method further includes:
[0035] Drive the ranging sensor to move to the second detection position so that the ranging sensor performs distance detection at the second detection position;
[0036] Based on the distance detected by the ranging sensor at the second detection position, it is determined whether the wafer has slid out of the wafer cassette.
[0037] In some embodiments, prior to the step of obtaining the distance detected by the ranging sensor at the first detection position, the method further includes:
[0038] If it is determined that the wafer has not slid out of the wafer cassette, the inside of the wafer cassette is scanned to obtain the slot status information in the wafer cassette.
[0039] Thirdly, this disclosure provides a wafer transport system, including the wafer loading and unloading equipment described above.
[0040] In this embodiment, a distance sensor can be used to detect distance at a first detection position. Based on the distance detected by the distance sensor at the first detection position, it can be determined whether the robot arm has entered or exited the wafer cassette. If it is determined that the robot arm has entered or exited the wafer cassette, the robot arm's wafer pick-up and placement information can be determined based on the distance detected by the distance sensor. This allows for real-time monitoring of the slot status during the robot arm's wafer transfer process, effectively reducing or avoiding the risk of robot arm collisions and improving equipment safety. Attached Figure Description
[0041] Figure 1 This is a schematic diagram of the wafer loading and unloading equipment provided in the embodiments of this disclosure.
[0042] Figure 2 This is a schematic diagram of a wafer loading / unloading device provided in an embodiment of the present disclosure performing a sliding detection.
[0043] Figure 3 This is a schematic diagram of the wafer loading and unloading equipment provided in this embodiment of the present disclosure during the robotic arm wafer picking process.
[0044] Figure 4 A schematic diagram of a controller provided in an embodiment of this disclosure.
[0045] Figure 5 This is a schematic diagram of the slot distribution within the wafer cell in an embodiment of this disclosure.
[0046] Figure 6 This is a schematic diagram of the driver, ranging sensor, and protective cover provided in an embodiment of this disclosure.
[0047] Figure 7 This is a flowchart of the wafer loading and unloading method provided in the embodiments of this disclosure. Detailed Implementation
[0048] To enable those skilled in the art to better understand the technical solutions of this disclosure, the disclosure will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0049] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “a,” “an,” “an,” “the,” and similar words used in this disclosure do not indicate quantity limitation and may indicate singular or plural. The terms “comprising,” “including,” “having,” and any variations thereof used in this disclosure are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units not listed, or may include other steps or units inherent to such processes, methods, products, or devices. The terms “connected,” “linked,” “coupled,” and similar words used in this disclosure are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. “Multiple” in this disclosure refers to two or more. “And / or” describes the relationship between related objects, indicating that three relationships may exist; for example, “A and / or B” can indicate: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following objects are in an "or" relationship. The terms "first," "second," "third," etc., used in this disclosure are merely to distinguish similar objects and do not represent a specific ordering of objects. "Above," "below," "left," "right," etc., are only used to indicate relative positional relationships; when the absolute position of the described objects changes, the relative positional relationship may also change accordingly.
[0050] In semiconductor manufacturing, after receiving a load command from the host computer, the wafer loading and unloading equipment loads the wafer cassette and opens it; then it scans the wafer cassette to obtain the slot status; afterwards, the robot removes the wafer from the wafer cassette and transfers it to the process processing area for processing; after the process processing is completed, the robot loads the processed wafer back into the wafer cassette.
[0051] Traditional wafer loading and unloading equipment cannot monitor the slot status in real time during the wafer transfer process (i.e., the pick-up and place-up processes) using a robotic arm. When the host computer sends a fault request to read the slot status information, the wafer loading and unloading equipment will upload the previous scan results, resulting in inaccurate slot status information received by the host computer, which can easily lead to malfunctions. For example, if the robotic arm continues to perform the pick-up and place-up operations, a collision may occur, damaging the robotic arm or the wafer.
[0052] To address the aforementioned technical problems, embodiments of this disclosure provide a wafer loading and unloading device. Figure 1 This is a schematic diagram of the wafer loading and unloading equipment provided in the embodiments of this disclosure. Figure 2 This is a schematic diagram illustrating the wafer loading / unloading equipment provided in this embodiment of the present disclosure, performing a sliding detection process. Figure 3 This is a schematic diagram of the wafer loading and unloading equipment provided in this embodiment of the disclosure during the robotic arm wafer picking process. Figures 1 to 3 As shown, the wafer loading and unloading equipment includes: a support platform 10, a ranging sensor 20, and a controller 30. The support platform 10 is used to support a wafer cassette 60, which has multiple slots for storing wafers 70, and the multiple slots are arranged sequentially along the height direction of the wafer cassette 60.
[0053] The ranging sensor 20 is configured to perform distance detection at least at a first detection position, which is located above the support platform 10, and the distance d1 between the first detection position and the support platform 10 is greater than the maximum distance d2 from the entrance / exit of the wafer cassette 60 to the support platform 10. The measuring end of the ranging sensor 20 faces the support platform 10. When the robot arm 40 is not entering or exiting the wafer cassette 60, the distance detected by the ranging sensor 20 at the first detection position is a first initial value; when the robot arm 40 enters or exits the wafer cassette 60, the distance detected by the ranging sensor 20 is less than the first initial value.
[0054] The first initial value can be the distance between the support platform 10 and the distance sensor 20; when the robot arm 40 enters or exits the wafer box 60, the distance detected by the distance sensor 20 at the first detection position is the distance between the robot arm 40 and the distance sensor 20.
[0055] It should be noted that, in this embodiment of the disclosure, "entering and exiting" the wafer cassette 60 means that the robotic arm 40 passes through the entrance and exit of the wafer cassette 60.
[0056] The controller 30 is configured to determine whether the robot arm 40 has entered or exited the wafer cassette 60 based on the distance detected by the distance sensor 20 at the first detection position, and when it is determined that the robot arm 40 has entered or exited the wafer cassette 60, to determine the wafer pick-up and placement information of the robot arm 40 based on the distance detected by the distance sensor 20 at the first detection position.
[0057] Since the distance actually detected by the ranging sensor 20 is different when the robotic arm 40 enters or exits the wafer cassette 60 and when it does not enter or exit the wafer cassette 60, it can be determined whether the robotic arm 40 has entered or exited the wafer cassette 60 based on the distance actually detected by the ranging sensor 20.
[0058] In one example, the pick-up and drop-off information may include the specific operation type performed by the robot arm 40, such as whether it is a pick-up operation or a drop-off operation; the pick-up and drop-off information may also include the slot corresponding to the pick-up and drop-off operation performed by the robot arm 40.
[0059] In the wafer loading and unloading equipment provided in this embodiment, the controller 30 can determine whether the robot arm 40 has entered or exited the wafer cassette 60 based on the distance detected by the distance sensor 20 at the first detection position. If it is determined that the robot arm 40 has entered or exited the wafer cassette 60, the controller 30 can determine the wafer picking and placing information of the robot arm 40 based on the distance detected by the distance sensor 20. This allows for real-time monitoring of the slot status during the wafer transfer process of the robot arm 40, effectively reducing or avoiding the risk of the robot arm 40 colliding with wafers and improving the safety of the equipment.
[0060] In some embodiments, the ranging sensor 20 is specifically configured to perform distance detection in real time, at least at a first detection position. For example... Figure 4 As shown, the controller 30 includes a sampling module 32 and a processing module 31.
[0061] The sampling module 32 is configured to sample the distance detected by the ranging sensor 20 at preset time intervals.
[0062] The processing module 31 is configured to determine whether the robotic arm 40 is entering or exiting the wafer cassette 60 based on the distance sampled by the sampling module 32. Specifically, when the distance sampled by the sampling module 32 is less than a first initial value, the processing module 31 can determine that the robotic arm 40 is entering or exiting the wafer cassette 60.
[0063] For example, if the sampling distance of the sampling module 32 at time t1 is the first initial value, the sampling distance from time t2 to time t5 is less than the first initial value, and the sampling distance at time t6 returns to the first initial value, then the processing module 31 can determine that the robot arm 40 enters and exits the wafer cassette 60 from time t2 to time t5. Time t2 to time t5 is the number of samplings during the process of the robot arm entering and exiting the wafer cassette 60, that is, one wafer pick-up and placement process of the robot arm (the robot arm 40 performs one wafer pick-up or wafer placement operation).
[0064] Furthermore, such as Figure 3As shown, when the robotic arm 40 picks up the wafer 70, its fingers rise to a certain height to support the wafer 70. Therefore, during the picking process, the sampling distance of the sampling module 32 at time t5 is less than the value at time t2. Similarly, when the robotic arm 40 places the wafer, its fingers descend to a certain height to leave the wafer 70. Therefore, during the placing process, the sampling distance of the sampling module 32 at time t5 is greater than the sampling distance at time t2. Based on this principle, the processing module 31 can further determine whether the operation performed by the robotic arm 40 is picking up or placing the wafer.
[0065] Specifically, during a single film acquisition process, as the sampling time increases, the sampling distance obtained by the sampling module 32 tends to decrease, resulting in a negative slope when reflecting a linear relationship; conversely, during a single film placement process, as the sampling time increases, the sampling distance obtained by the sampling module 32 tends to increase, resulting in a positive slope when reflecting a linear relationship. We can define the sampling time as x and the sampling distance as y, using a straight line to describe the relationship between time and distance, typically expressed as a linear equation: y = ax + b, where a is the slope and b is the intercept. The line that best fits the measured data is considered the "best fit." This "best fit" means that the line is as close as possible to all data points. To quantify the degree of closeness, we define the residual, which is the difference between the actual position value and the predicted value of each data point. The residual is minimized by calculating the sum of squared residuals, as shown in the formula... As shown, S is the sum of squared residuals. To find a and b that minimize S, we need to differentiate S and make the derivative equal to zero, i.e., find the extreme points. The expression for a is obtained by differentiating a and b respectively, as shown in equation (1) below:
[0066]
[0067] Where x is the sampling time, y is the sampling distance, and n is the number of samplings during one film loading and unloading process, where n is greater than 1.
[0068] In this embodiment, the processing module 31 is further configured to, when determining that the robotic arm 40 is entering or exiting the wafer cassette 60, determine whether the robotic arm 40 is performing a wafer placement operation or a wafer retrieval operation based on the relationship between the sampling distance and the sampling time. Specifically, as analyzed above, the relationship between the sampling distance and the sampling time satisfies the above linear equation. The processing module 31 can determine whether the robotic arm 40 is performing a wafer placement operation or a wafer retrieval operation based on the sign of the slope 'a' in the linear equation. When the slope 'a' in the linear equation is negative, it is determined that the robotic arm 40 is performing a wafer retrieval operation; when the slope 'a' in the linear equation is positive, it is determined that the robotic arm 40 is performing a wafer placement operation. Further, the processing module 31 can specifically determine the slope 'a' according to the above formula (1). When 'a' is negative, it is determined that the robotic arm 40 is performing a wafer retrieval operation; when 'a' is positive, it is determined that the robotic arm 40 is performing a wafer placement operation.
[0069] Furthermore, the processing module 31 is configured to, upon determining that the robotic arm 40 is performing a wafer picking and placing operation, determine the corresponding slot in the wafer 70 picked up and placed by the robotic arm 40 in the wafer cassette 60 based on the distance sampled by the sampling module 32 and the slot distribution information in the wafer cassette 60, thereby updating the slot status in the wafer cassette 60.
[0070] In some embodiments, the processing module 31 can be specifically configured to, when it is determined that the robot arm 40 is performing a wafer picking operation, determine the corresponding slot in the wafer cassette 60 where the wafer 70 picked up by the robot arm 40 is located based on the last sampling distance during the wafer picking process and the slot distribution information in the wafer cassette 60; and, when the second processing module 32 determines that the robot arm 40 is performing a wafer placement operation, determine the corresponding slot in the wafer cassette 60 where the wafer 70 placed by the robot arm 40 is located based on the first sampling distance during the wafer placement process and the slot distribution information in the wafer cassette 60, thereby reducing misjudgments caused by the shaking of the robot arm 40.
[0071] like Figure 5 As shown, the slot distribution information may include: the distance B between the topmost slot 61 in the wafer cassette 60 and the first detection position, the distance S between two adjacent slots 61, and the total number N of slots 61. In one example, when the robot arm 40 performs a wafer picking operation, the last sampling distance obtained by the sampling module 32 during the wafer picking process is H1. Then, according to the formula N-(H1-B+K*S) / S, the number of slot layers corresponding to the wafer 70 picked up by the robot arm 40 is calculated, and the result is an integer value. When the robot arm 40 performs a wafer placement operation, the first sampling distance obtained by the sampling module 32 during the wafer placement process is H2. Then, according to the formula N-(H2-B+K*S) / S, the number of slot layers corresponding to the wafer 70 placed by the robot arm 40 is calculated, and the result is an integer value. Here, K in the formula is the detection error coefficient, which can be adjusted according to the actual situation, for example, K=0.5.
[0072] In some embodiments, the controller 30 is further configured to generate a first alarm signal when the distance detected by the ranging sensor 20 is less than the first initial value for a period of time exceeding a preset duration. Specifically, if the distance detected by the ranging sensor 20 is less than the first initial value for an extended period, it indicates that the robotic arm 40 has failed to pick up or place the piece, and the controller 30 generates the first alarm signal and can send it to the host computer.
[0073] In some embodiments, such as Figures 1 to 3 As shown, the wafer loading and unloading equipment may also include: a door opening mechanism 90, which is configured to open the wafer cassette 60 in response to a loading command from the host computer, so that the robot arm 40 can perform wafer loading and unloading operations.
[0074] During the process of the opening mechanism 90 opening the wafer cassette 60, the wafer 70 may slide out of the wafer cassette 60. To address this issue, the wafer loading and unloading device in this embodiment of the present disclosure also has a slip detection function. Specifically, in some embodiments, the wafer loading and unloading device may further include a support 11 and a driver 50 mounted on the support 11. The driver 50 is connected to a ranging sensor 20 and configured to drive the ranging sensor 20 to move between a first detection position and a second detection position. The ranging sensor 20 is also configured to perform distance detection at the second detection position. When the wafer 70 has not slid out of the wafer cassette 60, the distance detected by the ranging sensor 20 at the second detection position is a second initial value; when at least one wafer 70 has slid out of the wafer cassette 60, the distance detected by the ranging sensor 20 at the second detection position is less than the second initial value. In one example, the second detection position and the first detection position are at the same height, and the second detection position is located on the side of the first detection position closer to the wafer cassette 60. In this case, the second initial value is equal to the first initial value.
[0075] The controller 30 is further configured to determine whether the wafer 70 has slipped out of the wafer cassette 60 based on the distance detected by the ranging sensor 20 at the second detection position, and to generate a second alarm signal when it is determined that the wafer 70 has slipped out of the wafer cassette 60. This second alarm signal can be reported to the host computer.
[0076] In this embodiment of the disclosure, the same ranging sensor 20 is used for both the detection of the sliding sheet and the detection of the picking and placing of the sheet by the robotic arm 40, which can save materials and reduce costs.
[0077] In some embodiments, such as Figure 6 As shown, the actuator 50 can be, for example, a cylinder. The actuator 50 includes a body 51 and a drive shaft 52 connected to the body 51, the drive shaft 52 being connected to the ranging sensor 20. The drive shaft 52 is used to drive the ranging sensor 20 to move between a first detection position and a second detection position.
[0078] In some embodiments, the orthographic projection of the second detection position on the reference plane lies between the orthographic projection of the first detection position on the reference plane and the orthographic projection of the wafer cassette 60 on the reference plane. The reference plane is the plane on which the stage 10 is located.
[0079] Furthermore, the extension direction of the drive shaft 52 is parallel to the bearing surface of the support stage 10, which is the surface of the support stage 10 used to support the wafer cassette 60. The first detection position and the second detection position are arranged along the extension direction of the drive shaft 52. It should be noted that "parallel" in the embodiments of this disclosure includes absolute parallelism and approximately parallelism, wherein the acceptable deviation range for approximately parallelism can be, for example, within 5°.
[0080] In some embodiments, the wafer loading and unloading equipment further includes a protective cover 53, which covers the outside of the ranging sensor 20 and the drive shaft 52, thereby isolating the ranging sensor 20 and the drive shaft 52 from the outside air and preventing particle diffusion during the movement of the drive shaft 52 from affecting the surface quality of the wafer 70. The ranging sensor 20 may be a laser sensor, and the protective cover 53 is made of a transparent material to prevent interference with the measurement results of the ranging sensor 20.
[0081] In some embodiments, such as Figures 1 to 3 As shown, the wafer loading and unloading equipment may further include a scanning mechanism 80, which is configured to scan the inside of the wafer cassette 60 to obtain slot status information in the wafer cassette 60 when the controller 30 determines that the wafer 70 has not slid out of the wafer cassette 60.
[0082] This disclosure also provides a wafer loading and unloading method, combined with... Figures 1 to 3 As shown, the wafer loading and unloading method includes:
[0083] S10. Obtain the distance detected by the ranging sensor 20 at the first detection position. The first detection position is located above the support platform 10, which supports the wafer cassette 60. The wafer cassette 60 has multiple slots for storing wafers 70. The distance between the first detection position and the support platform 10 is greater than the maximum distance from the entrance / exit of the wafer cassette 60 to the support platform 10. The measuring end of the ranging sensor 20 faces the support platform 10. When the robot arm 40 is not entering or exiting the wafer cassette 60, the distance detected by the ranging sensor 20 at the first detection position is a first initial value. When the robot arm 40 enters or exits the wafer cassette 60, the distance detected by the ranging sensor 20 is less than the first initial value.
[0084] S20. Based on the distance detected by the ranging sensor 20 at the first detection position, determine whether the robotic arm 40 has entered or exited the wafer box 60.
[0085] S30. When it is determined that the robot arm 40 enters or exits the wafer box 60, the wafer picking and placing information of the robot arm 40 is determined according to the distance detected by the distance sensor 20 at the first detection position.
[0086] The wafer loading and unloading method will be described in detail below with reference to the accompanying diagram. Figure 7 As shown, the wafer loading and unloading method includes not only the steps S10 to S30 described above, but also the following steps S01 to S05 performed before step S10:
[0087] S01. In response to the host's loading command, open wafer cassette 60.
[0088] S02, drive the ranging sensor 20 to move to the second detection position so that the ranging sensor 20 can perform distance detection at the second detection position. Wherein, when the wafer 70 has not slid out of the wafer cassette 60, the distance detected by the ranging sensor 20 at the second detection position is the second initial value; when the wafer 70 has slid out of the wafer cassette 60, the distance detected by the ranging sensor 20 at the second detection position is less than the second initial value.
[0089] S03. Based on the distance actually detected by the ranging sensor 20 at the second detection position, determine whether the wafer 70 has slid out of the wafer box 60.
[0090] For example, if it is determined in step S03 that the wafer 70 has slid out of the wafer cassette 60, a second alarm signal is generated and sent to the host, thereby ending the process; if it is determined that the wafer 70 has not slid out of the wafer cassette 60, then proceed to step S04.
[0091] S04. Scan the wafer cell 60 to obtain the slot status information in the wafer cell 60.
[0092] S05. Drive the ranging sensor 20 to move to the first detection position so that the ranging sensor 20 can perform distance detection in real time at the first detection position.
[0093] In some embodiments, after step S05, steps S10 and S20 are performed. Step S20 may include steps S21 to S23:
[0094] S21. Sample the distance detected by the ranging sensor 20 at the first detection position according to the preset time interval.
[0095] S22. Determine if timeout has occurred, that is, determine whether the distance detected by the ranging sensor 20 at the first detection position is less than the first initial value within a time period exceeding the preset duration. If so, generate the first alarm signal and send it to the host, thereby ending the process; otherwise, continue to step S23.
[0096] S23. Based on the sampled distance, determine whether the robotic arm 40 has entered or exited the wafer box 60.
[0097] When it is determined in step S23 that the robotic arm 40 enters or exits the wafer cassette 60, step S30 is executed. The wafer pick-up / placement information in step S30 may include the type of operation performed by the robotic arm, such as whether it is a pick-up or place-up operation. Additionally, the wafer pick-up / placement information may also include the slot corresponding to the wafer pick-up / placement operation performed by the robotic arm 40.
[0098] In some embodiments, step S30 may include steps S31 to S32:
[0099] S31. Based on the trend of the sampling distance over time, determine whether the robotic arm 40 is performing a film picking operation or a film placing operation.
[0100] S32. Determine the corresponding slot in the wafer box 60 where the wafer picked up or placed by the robot arm 40 is located based on the sampling distance.
[0101] In some embodiments, step S31 may specifically include: determining whether the robotic arm 40 is performing a wafer picking operation or a wafer placement operation based on the trend of the sampling distance changing over time.
[0102] As analyzed above, the relationship between sampling distance and sampling time satisfies a linear equation. In step S31, the robot arm can be judged to perform a pick-up or drop-off operation based on the slope 'a' in the linear equation satisfied by the sampling distance and sampling time. When the slope 'a' is negative, the robot arm 40 is determined to pick up the chip; when the slope 'a' in the linear equation is positive, the robot arm 40 is determined to drop the chip. Specifically, the slope 'a' is determined according to the following formula (1). When 'a' is negative, the robot arm 40 is determined to pick up the chip; when 'a' is positive, the robot arm 40 is determined to drop the chip.
[0103]
[0104] Where x is the sampling time, y is the sampling distance, and n is the number of samplings during one film loading and unloading process.
[0105] Furthermore, based on the sampled distance, the corresponding slot in the wafer cassette 60 where the robotic arm 40 picks up or places the wafer 70 can be determined, thereby updating the slot status information.
[0106] In some embodiments, step S32 may specifically include: if it is determined that the robot arm 40 is performing a wafer picking operation, then when determining the slot position, the slot position of the wafer 70 picked up by the robot arm 40 in the wafer cassette 60 is determined according to the last sampling distance in the wafer picking process and the slot position distribution information; if it is determined that the robot arm 40 is performing a wafer placement operation, then when determining the slot position, the slot position of the wafer 70 placed by the robot arm 40 in the wafer cassette 60 is determined according to the first sampling distance in the wafer picking process and the slot position distribution information.
[0107] After step S32, proceed to step S40: determine whether an unload command from the host has been received. If yes, the process ends; otherwise, return to step S20 to continue the determination.
[0108] This disclosure also provides a wafer transport system, which includes the wafer loading and unloading equipment described in the above embodiments.
[0109] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.
Claims
1. A wafer loading and unloading device, characterized in that, include: A support platform for supporting a wafer cassette, the wafer cassette having multiple slots for storing wafers; A ranging sensor is configured to detect distance at least at a first detection position, the first detection position being located above the support platform, and the distance between the first detection position and the support platform being greater than the maximum distance from the wafer cassette's entrance / exit to the support platform; the measuring end of the ranging sensor faces the support platform; wherein, when the robot arm is not entering or exiting the wafer cassette, the distance detected by the ranging sensor at the first detection position is a first initial value; when the robot arm enters or exits the wafer cassette, the distance detected by the ranging sensor is less than the first initial value; The controller is configured to determine whether the robotic arm has entered or exited the wafer cassette based on the distance detected by the ranging sensor at the first detection position, and, if it is determined that the robotic arm has entered or exited the wafer cassette, to determine the wafer pick-up and placement information of the robotic arm based on the distance detected by the ranging sensor at the first detection position.
2. The wafer loading and unloading equipment according to claim 1, characterized in that, The wafer loading and unloading equipment further includes a driver for driving the distance sensor to move. The driver includes a body and a drive shaft connected to the body. The drive shaft is connected to the distance sensor. The drive shaft is used to drive the distance sensor to move between the first detection position and the second detection position.
3. The wafer loading and unloading equipment according to claim 2, characterized in that, The orthographic projection of the second detection position on the reference plane is located between the orthographic projection of the first detection position on the reference plane and the orthographic projection of the wafer cell on the reference plane, where the reference plane is the plane where the support stage is located.
4. The wafer loading and unloading equipment according to claim 2, characterized in that, The wafer loading and unloading equipment further includes a protective cover, which covers the outside of the ranging sensor and the drive shaft.
5. The wafer loading and unloading equipment according to any one of claims 1 to 4, characterized in that, The controller is also configured to determine whether the wafer has slid out of the wafer cassette; The wafer loading and unloading equipment also includes: The scanning mechanism is configured to scan the inside of the wafer cassette to obtain slot status information in the wafer cassette when the controller determines that the wafer has not slid out of the wafer cassette.
6. A wafer loading and unloading method, characterized in that, include: The distance detected by the ranging sensor at a first detection position is obtained; wherein the first detection position is located above a support platform, the support platform is used to support a wafer cassette, the wafer cassette has multiple slots for storing wafers, and the distance between the first detection position and the support platform is greater than the maximum distance from the wafer cassette's entrance / exit to the support platform; the measuring end of the ranging sensor faces the support platform; wherein, when the robot arm is not entering or exiting the wafer cassette, the distance detected by the ranging sensor at the first detection position is a first initial value; when the robot arm enters or exits the wafer cassette, the distance detected by the ranging sensor is less than the first initial value; Based on the distance detected by the ranging sensor at the first detection position, it is determined whether the robotic arm enters or exits the wafer cassette; When it is determined that the robotic arm is entering or leaving the wafer cassette, the wafer picking and placing information of the robotic arm is determined based on the distance detected by the distance measuring sensor at the first detection position.
7. The wafer loading and unloading method according to claim 6, characterized in that, The step of determining whether the robotic arm has entered or exited the wafer cassette based on the distance detected by the ranging sensor at the first detection position specifically includes: The distance detected by the ranging sensor is sampled at preset time intervals; The robotic arm is used to determine whether it enters or exits the wafer cassette based on the sampling distance.
8. The wafer loading and unloading method according to claim 7, characterized in that, The step of determining the robotic arm's wafer pick-up and placement information based on the distance detected by the ranging sensor at the first detection position when it is determined that the robotic arm has entered or exited the wafer cassette specifically includes: Based on the relationship between sampling distance and sampling time, it can be determined whether the robotic arm is performing a wafer picking operation or a wafer placement operation; The sampling distance determines the corresponding slot in the wafer cassette for the wafer picked up or placed by the robotic arm.
9. The wafer loading and unloading method according to claim 8, characterized in that, The relationship between the sampling distance and the sampling time satisfies a linear equation; The step of determining whether the robotic arm is performing a wafer picking or placing operation based on the relationship between sampling distance and sampling time specifically includes: The sign of the slope in the linear equation is determined. When the slope is negative, the robot arm is determined to perform a wafer picking operation; when the slope is positive, the robot arm is determined to perform a wafer placement operation.
10. The wafer loading and unloading method according to claim 8, characterized in that, The step of determining the corresponding slot in the wafer cassette for the wafer picked up and placed by the robotic arm based on the sampling distance specifically includes: When it is determined that the robotic arm is performing a wafer picking operation, the slot in the wafer cassette corresponding to the wafer picked up by the robotic arm is determined based on the last sampling distance during the wafer picking process. When it is determined that the robotic arm is performing a wafer placement operation, the slot in the wafer cassette corresponding to the wafer placed by the robotic arm is determined based on the first sampling distance during the wafer placement process.
11. The wafer loading and unloading method according to any one of claims 6 to 10, characterized in that, The wafer loading and unloading method also includes: When the ranging sensor at the first detection position detects the first initial value for a time exceeding a preset duration, a first alarm signal is generated.
12. The wafer loading and unloading method according to any one of claims 6 to 10, characterized in that, Before the step of acquiring the distance detected by the ranging sensor at the first detection position, the method further includes: Drive the ranging sensor to move to the second detection position so that the ranging sensor performs distance detection at the second detection position; Based on the distance detected by the ranging sensor at the second detection position, it is determined whether the wafer has slid out of the wafer cassette.
13. The wafer loading and unloading method according to claim 12, characterized in that, Before the step of acquiring the distance detected by the ranging sensor at the first detection position, the method further includes: If it is determined that the wafer has not slid out of the wafer cassette, the inside of the wafer cassette is scanned to obtain the slot status information in the wafer cassette.
14. A wafer transmission system, characterized in that, The wafer loading and unloading equipment includes any one of claims 1 to 5.