A substrate automatic aligning method and system based on asymmetric developing tank

Abstract

The application discloses a kind of substrate automatic righting method and system based on asymmetric developing tank, the method includes: providing the developing tank with rectangular work area and right-angle trapezoidal area consisting of top view profile, two areas have distinguishable visual features;Collecting substrate top view image;Based on visual feature segmentation area and extract substrate profile and reference edge;Calculate the translational deviation and rotational deviation of current substrate relative to ideal righting template;Control manipulator closed-loop adjustment until deviation is up to standard.The application realizes mark-free positioning by using the asymmetric trapezoidal structure and color difference of developing tank itself, without additional processing positioning mark;Through closed-loop iterative control and multi-level self-checking mechanism, the precision and reliability of substrate righting are significantly improved, and different shapes and sizes of substrate can be self-adapted.The application is suitable for developing process in photolithography.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing equipment technology, and more specifically, to an automatic substrate alignment method and system based on an asymmetric developing tank. Background Technology

[0002] In photolithography processes used in semiconductor manufacturing, flat panel displays, and microelectromechanical systems (MEMS), the development process is a critical step. During development, the substrate (such as a silicon wafer or glass substrate) needs to be precisely placed in the developing tank to ensure that the developer uniformly covers the substrate surface, thereby achieving good pattern transfer quality. The placement orientation of the substrate in the developing tank—including the alignment accuracy between its center and the tank center, and the horizontal orientation of the substrate's reference edge—directly affects the uniformity of development, the effectiveness of removing residual photoresist from the edges, and the alignment accuracy of subsequent processes.

[0003] Traditional substrate alignment operations typically rely on manual visual inspection or simple mechanical positioning. Manual operation is inefficient, lacks repeatability, and is prone to human error; mechanical positioning requires changing different positioning components for substrates of different sizes and shapes, resulting in poor flexibility, and the contact between the positioning components and the substrate edges may cause damage. As substrate sizes continue to increase and process precision requirements become increasingly stringent, traditional alignment methods are no longer sufficient to meet the needs of automated production lines.

[0004] In recent years, several automated substrate alignment technologies have been proposed. For example, by placing specialized positioning marks or sensors within the developing tank, combined with image acquisition and processing algorithms, the automatic detection and adjustment of the substrate's pose can be achieved. However, these solutions often require additional machining of positioning marks on the developing tank, increasing the complexity of tank manufacturing; the marks may also be corroded or contaminated after prolonged contact with the developer, leading to identification failure. Furthermore, some solutions rely on complex external calibration devices, resulting in high system costs and difficult maintenance.

[0005] Another common approach is to directly set alignment marks on the substrate, achieving alignment by recognizing the marks on the substrate itself. However, substrates from different batches or manufacturers may have different mark shapes and positions, resulting in poor algorithm versatility and making it unsuitable for substrates without pre-made alignment marks.

[0006] Therefore, how to achieve rapid, accurate, and automatic alignment of the substrate in the developing tank without adding extra markings to the developing tank or relying on specific markings on the substrate itself, and how to adapt to substrates of different shapes and sizes, while also having the ability to self-check the installation errors of the image acquisition device, is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] To overcome the above-mentioned defects of the prior art, embodiments of the present invention provide an automatic substrate alignment method and system based on an asymmetric developing tank.

[0008] To achieve the above objectives, this invention provides an automatic substrate alignment method based on an asymmetric developing tank, with the following innovative features: It includes the following steps:

[0009] Step 1: Providing a developing tank: A developing tank is provided, the top view of which consists of a rectangular working area and a right-angled trapezoidal area; the rectangular working area and the right-angled trapezoidal area have different colors; at least two recovery funnels protruding from the bottom surface of the developing tank are provided on the hypotenuse side of the right-angled trapezoidal area;

[0010] Step 2: Install the image acquisition device: Install the image acquisition device above the rectangular work area so that its field of view covers the entire developing tank;

[0011] Step 3: Camera installation posture self-calibration: Acquire an empty image of the developing tank, identify the centers of at least two recovery funnels, calculate the angle between the line connecting their centers and the horizontal reference side of the rectangular working area, and if the angle exceeds the preset range, perform error compensation or issue an adjustment prompt.

[0012] Step 4: Establish the ideal alignment template: Define the target pose of the substrate relative to the rectangular work area;

[0013] Step 5: Acquire a top view image: Acquire a top view image of the substrate placed in the developing tank;

[0014] Step 6: Segment the region and extract the outline: Segment the rectangular working area and the right-angled trapezoidal area based on different colors, and extract the current substrate outline and substrate reference edge;

[0015] Step 7: Calculate translation and rotation deviations: Calculate the translation and rotation deviations of the current substrate relative to the ideal aligned template;

[0016] Step 8: Substrate Placement Verification: Detect whether the edge of the substrate obstructs the recycling funnel; if the obstruction area exceeds a preset threshold, the substrate placement is deemed to have failed, an alarm signal is issued and the placement process is terminated; otherwise, continue with the subsequent steps.

[0017] Step 9: Adaptively set translation and rotation thresholds based on the substrate size; then determine whether the translation deviation is less than the preset translation threshold and whether the rotation deviation is less than the preset rotation threshold; if yes, the substrate is successfully positioned and the process ends; if no, control the robot arm to adjust the substrate pose according to the deviation, and then return to Step 5.

[0018] Furthermore, in the step of self-calibrating the camera installation attitude using the line connecting the centers of the recycling funnels, when there are more than two funnels, the line connecting the centers of the two funnels that are furthest apart is selected first.

[0019] Furthermore, the ideal alignment template is defined as follows: the geometric center of the substrate coincides with the geometric center of the rectangular working area, and the reference edge of the substrate is parallel to the horizontal reference edge of the rectangular working area; the translation deviation is the Euclidean distance between the geometric center of the substrate and the geometric center of the rectangular working area in the image coordinate system, and the rotation deviation is the angle between the reference edge of the substrate and the horizontal reference edge of the rectangular working area.

[0020] Furthermore, when the robotic arm adjusts its pose, if the edge of the substrate exceeds the boundary of the rectangular working area, it will first translate and pull it back before rotating; otherwise, it will prioritize rotation adjustment before translation adjustment.

[0021] Furthermore, the right-angled legs of the right trapezoidal region are parallel to the horizontal line, and both the longer and shorter parallel sides of the right trapezoidal region are perpendicular to the horizontal line. The shorter parallel side is located on the side away from the rectangular work area, while the longer parallel side coincides with one side of the rectangular work area.

[0022] Furthermore, the preset translation threshold is adaptively set in a positive correlation with the substrate feature size, while the preset rotation threshold is a fixed value.

[0023] Furthermore, the substrate is rectangular, and the reference edge of the substrate is any one of its sides.

[0024] Furthermore, the substrate is circular, and its reference direction is the preset missing edge direction or the marked point direction; in the ideally placed template, the center of the circle coincides with the center of the rectangular work area, and the periphery of the circle maintains a preset gap with the boundary of the rectangular work area.

[0025] Furthermore, the substrate placement verification step also includes: determining whether the substrate has warped or tilted by observing the change in the relative projection position between the substrate edge and the funnel protrusion.

[0026] This invention provides an automatic substrate alignment system based on an asymmetric developing tank, comprising:

[0027] The asymmetric developing tank has a top view profile consisting of a rectangular working area and a right-angled trapezoidal area, with the rectangular working area and the right-angled trapezoidal area having different colors; the hypotenuse of the right-angled trapezoidal area is provided with at least two recovery funnels protruding from the bottom surface of the tank.

[0028] The image acquisition device is installed directly above the rectangular work area, and its field of view covers the entire developing tank.

[0029] A robotic arm is used to pick up, place, and adjust substrates;

[0030] The controller is configured to execute the above method.

[0031] The technical effects and advantages of this invention are as follows:

[0032] 1. Utilizing the asymmetric geometric features of the developing tank itself to achieve marker-free positioning significantly reduces system complexity and maintenance costs:

[0033] This invention employs an asymmetrical structure within the developing tank's top-view profile, consisting of a rectangular working area and a right-angled trapezoidal area. These two areas are given distinct visual characteristics (such as different colors), and the recovery funnel at the hypotenuse of the right-angled trapezoidal area serves as an auxiliary optical feature. This allows the developing tank itself to possess a uniquely identifiable spatial reference system. The image acquisition device can directly perform region segmentation, pose calibration, and deviation measurement based on these fixed features, eliminating the need for any additional specialized positioning marks or alignment patterns on the developing tank, and also eliminating reliance on the substrate's own alignment marks. This design fundamentally avoids the problems of marks being corroded or contaminated by the developing solution or failing due to long-term use, reducing the manufacturing and maintenance difficulty of the developing tank. Furthermore, because it does not rely on specific substrate marks, this invention has good versatility for substrates from different manufacturers and batches, broadening the system's applicability.

[0034] 2. Construct a closed-loop iterative control and multi-level self-verification mechanism to achieve high precision and high reliability in substrate alignment:

[0035] This invention acquires real-time top-view images of the substrate and developing tank using an image acquisition device. Based on a pre-calibrated ideal alignment template, it calculates the translational deviation between the geometric center of the substrate and the center of the rectangular working area, as well as the rotational deviation between the substrate reference edge and the horizontal reference edge. A controller drives a robotic arm to perform closed-loop iterative adjustments until the deviations meet a preset threshold. This closed-loop control logic eliminates potential system errors remaining from single open-loop adjustments, enabling stable substrate alignment to sub-millimeter and sub-angle accuracy. Furthermore, this invention utilizes the angle between the line connecting the centers of the recovery funnel within the right-angled trapezoidal area and the horizontal reference edge to self-check and compensate for errors in the installation posture of the image acquisition device, effectively suppressing the impact of camera installation deviations on measurement accuracy. Simultaneously, by monitoring the area of ​​the substrate edge obstructing the protruding structure of the recovery funnel and the change in its relative projection, it can determine in real-time whether the substrate has warped, tilted, or failed to be placed, and issue timely alarms. This multi-level self-checking and anomaly detection mechanism comprehensively ensures the accuracy and reliability of the alignment operation from the source to the process, making it particularly suitable for large-scale automated production of high-value substrates. Attached Figure Description

[0036] Figure 1 Top view of the developing tank.

[0037] Figure 2 Flowchart of the automatic substrate alignment method.

[0038] Figure 3 A schematic diagram of image segmentation and feature extraction.

[0039] Figure 4 Block diagram of the automatic substrate alignment system.

[0040] The labels and the structural names they represent in the attached diagram are as follows:

[0041] 100 - Asymmetric developing tank; 110 - Rectangular working area; 111 - Horizontal reference side; 112 - Right-angled side; 120 - Right-angled trapezoidal area; 121 - Right-angled waist; 122 - Shorter parallel side; 123 - Longer parallel side; 124 - Hypotenuse; 130 - Recovery funnel; 1 - Substrate; 11 - Substrate reference side; 12 - Geometric center of substrate; 13 - Geometric center of rectangular working area. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] Example 1: Structure and positioning of the developing tank

[0044] This embodiment first describes in detail the physical basis upon which the present invention is based—the specific structure of an asymmetric developing tank.

[0045] like Figure 1 As shown, the top view of the asymmetric developing tank 100 provided in this embodiment consists of a rectangular working area 110 and a right-angled trapezoidal area 120. The rectangular working area 110 is used to accommodate the substrate 1 to be developed, and it has a horizontal reference side 111 and a right-angled side 112. The right-angled trapezoidal area 120 is adjacent to the rectangular working area 110, its right-angled side 121 is parallel to the horizontal line, its longer parallel side 123 coincides with one side of the rectangular working area 110, and its shorter parallel side 122 is located on the side away from the rectangular working area 110. Both the longer parallel side 123 and the shorter parallel side 122 are perpendicular to the horizontal line. The hypotenuse 124 serves as the asymmetric feature. Here, "horizontal line" refers to the horizontal axis direction of the image acquired by the image acquisition device. Provided that the camera is correctly installed (the optical axis is perpendicular to the plane of the rectangular working area), this horizontal line is parallel to the horizontal reference side of the rectangular working area.

[0046] To achieve fast and stable region segmentation in image processing, the rectangular working area 110 and the right-angled trapezoidal area 120 are coated with different colors; for example, the rectangular working area 110 is dark and the right-angled trapezoidal area 120 is light. Considering the potential chemical corrosiveness of the developing solution, this color coating is preferably achieved using a chemically resistant process, such as anodizing, ceramic coating, or acid and alkali resistant paint, thereby creating distinguishable visual features during image acquisition. Furthermore, two recovery funnels 130 protruding from the bottom of the developing tank are provided near the hypotenuse 124 of the right-angled trapezoidal area 120 for collecting the developing solution. The protruding structure of the recovery funnels 130 creates recognizable optical features, such as circular shadows, in the top-view image.

[0047] Unlike conventional asymmetric markers used only for positioning, the right-angled trapezoidal area 120 and the recovery funnel 130 on its hypotenuse 124 side in this invention not only provide the asymmetric reference required for visual positioning, but the geometric relationship of its center is also creatively used for online verification of the installation posture of the image acquisition device. Simultaneously, its physical protrusion characteristics are used to monitor the placement status of the substrate 1 in real time (such as occlusion or warping). This "multi-functional" approach to the developing tank's own process structure enables camera self-calibration and placement verification without additional sensors or calibration components, which is one of the key technical features of this invention for achieving high-precision, high-reliability automatic alignment.

[0048] During automatic substrate alignment, the ideal alignment posture is pre-defined as follows: the geometric center 12 of the substrate coincides with the geometric center 13 of the rectangular working area, the reference edge 11 of the substrate is parallel to the horizontal reference edge 111 of the rectangular working area 110, and all edges of the substrate 1 are within the boundary of the rectangular working area 110. Through the aforementioned asymmetrical right-angled trapezoidal area design and color differences, combined with the geometric features of the recovery funnel 130, this invention enables rapid segmentation and positioning of the developing tank in the image without the need for additional marker points, providing a structural foundation for high-precision alignment.

[0049] Example 1.1: Offline calibration of an ideal alignment template

[0050] After the system is used for the first time or after maintenance, a template calibration procedure must be performed. The details are as follows:

[0051] Ensure the developing tank is empty and the bottom is clean, and that the image acquisition device is securely installed;

[0052] Acquire a top-view image and segment the rectangular working area based on the color difference between the rectangular working area and the right-angled trapezoidal area;

[0053] The four sides of the rectangular working area are extracted using Hough line detection, and the intersection points are calculated to obtain the four corner points, thereby determining the pixel coordinates of the geometric center of the rectangular working area in the image;

[0054] Select the side of the rectangular work area that is opposite to the longer parallel side of the right trapezoidal area (i.e. the side away from the trapezoidal area) as the horizontal reference side and record its straight line equation;

[0055] Store the aforementioned geometric center coordinates and horizontal reference edge direction as parameters for the ideal alignment template. For circular substrates, it is also necessary to preset the gap value between the circumference and the boundary when the center of the circle coincides with the center of the rectangle (e.g., 2mm).

[0056] Example 2: Automatic Alignment Method

[0057] This embodiment describes in detail the automatic substrate alignment method based on the developing tank described in Embodiment 1, and its overall control flow is as follows: Figure 2 As shown.

[0058] refer to Figure 2 The automatic substrate alignment method of the present invention specifically includes the following steps:

[0059] First, execute the initialization configuration: "Provide a developing tank"—provide a developing tank whose top view consists of a rectangular working area and a right-angled trapezoidal area. The two areas are different colors, and the hypotenuse of the right-angled trapezoidal area has at least two recovery funnels protruding from the bottom of the tank. Then, "Install image acquisition device"—install the image acquisition device above the rectangular working area so that its field of view covers the entire developing tank.

[0060] Next, offline calibration and self-calibration are performed: "Camera Mounting Posture Self-calibration"—acquires an empty image of the developing tank, identifies the centers of at least two recovery funnels, calculates the angle between the line connecting their centers and the horizontal reference side of the rectangular working area, and if the angle exceeds the preset range, error compensation is performed or an adjustment prompt is issued. "Establish Ideal Positioning Template"—defines the target pose of the substrate relative to the rectangular working area.

[0061] Then it enters the main closed-loop process:

[0062] "Acquire top view image" - Acquire a top view image of the substrate placed in the developing tank.

[0063] "Segment the region and extract the contour" - Based on different colors, the rectangular working area and the right-angled trapezoidal area are segmented to extract the current substrate contour and the substrate reference edge.

[0064] "Calculate translational and rotational deviations" - Calculate the translational and rotational deviations of the current substrate relative to the ideally aligned template.

[0065] "Substrate Placement Verification" – This function checks whether the substrate edge is obstructing the recycling funnel. If the obstruction area exceeds a preset threshold, the substrate placement is deemed to have failed, and the system proceeds along the right-hand abnormal branch to "Alarm and Terminate" (issues an alarm signal and terminates the placement process); otherwise, the verification passes, and subsequent steps continue.

[0066] "Does the deviation meet the standard?": First, adaptively set the translation and rotation thresholds based on the substrate size. Then, determine whether the translation deviation is less than the preset translation threshold and the rotation deviation is less than the preset rotation threshold. If yes, the placement is successful and the process ends; otherwise, proceed to "Robot Arm Adjusts Pose" (controlling the robot arm to adjust the substrate pose according to the deviation), and then return to the "Acquire Top View Image" step through the left loop. Repeat the above loop until the deviation meets the standard or placement fails and the process terminates.

[0067] Furthermore, as a preferred embodiment, when the robot adjusts its pose, if the edge of the substrate exceeds the boundary of the rectangular working area, it is first translated and pulled back before rotation; otherwise, rotation adjustment is performed first, followed by translation adjustment.

[0068] like Figure 3 As shown, in the acquired top-view image, the rectangular working area 110 and the right-angled trapezoidal area 120 have distinguishable visual features (illustrated by different fill patterns). The horizontal reference side 111 (dotted line) and the right-angled side 112 (solid line) of the rectangular working area 110 are pre-labeled as fixed geometric features; the hypotenuse 124 (double-dotted line) and the right-angled waist 121 (solid line) of the right-angled trapezoidal area 120 are also used for auxiliary positioning. The figure also shows two recovery funnels 130 (concentric circles), whose convex structures form recognizable optical features in the image. The substrate 1 is placed within the rectangular working area 110. The figure schematically shows the cases where the geometric center 12 of the substrate does not coincide with the geometric center 13 of the rectangular working area (translational deviation), and the substrate reference side 11 is not parallel to the horizontal reference side 111 (rotational deviation). These features can be extracted for deviation calculation through image segmentation and line detection.

[0069] Example 3: Automatic Alignment System

[0070] This embodiment describes an automatic substrate alignment system for implementing the above method. For example... Figure 4 As shown, the system mainly includes an asymmetric developing tank 100, an image acquisition device, a robotic arm, and a controller.

[0071] The asymmetric developing tank 100 has the specific structure described in Embodiment 1, and its top view profile consists of a rectangular working area 110 and a right-angled trapezoidal area 120. The image acquisition device is preferably a color camera, mounted directly above the rectangular working area 110, with its optical axis perpendicular to the plane of the rectangular working area 110, ensuring that its field of view covers the entire developing tank 100. A robotic arm is used to respond to control commands, performing the picking and placing of the substrate 1 and precise pose adjustment.

[0072] The controller is the core of this system. For example... Figure 4As shown in the signal flow diagram, the controller receives top-view image data from the image acquisition device and obtains the tank position status information fed back by the asymmetric developing tank 100. The controller is internally configured with an image processing module, a deviation calculation module, a threshold adaptive module, and an anomaly alarm module (internal modules are not shown in the figure), and is configured to execute the automatic substrate alignment method as described in Example 2. After calculating the deviation according to a preset algorithm, the controller sends precise control commands to the robotic arm, driving the robotic arm to adjust the pose of the substrate 1, thereby achieving automatic alignment of the substrate 1 within the developing tank.

[0073] Example 4: Image Acquisition Device Attitude Verification

[0074] This embodiment focuses on how to use the structural features of the developing tank itself to verify the installation posture of the image acquisition device, which is a key prerequisite for ensuring measurement accuracy.

[0075] As described in Embodiment 1, two protruding recycling funnels 130 are provided within the right-angled trapezoidal area 120. These two recycling funnels 130 form a recognizable optical feature in the image, such as a circle. During system initialization or periodic maintenance, the controller executes a verification procedure: first, the center position of the recycling funnel 130 is extracted from the top-view image. In this embodiment, two funnels are provided, so this is directly used. If the system is configured with more than two funnels, the centers of the two funnels furthest apart are selected to reduce the impact of center positioning error on the angle calculation, and the equation of the straight line connecting the two centers is calculated. Then, the angle between this line and the horizontal reference side 111 of the rectangular working area 110 in the image is calculated.

[0076] Theoretically, if the optical axis of the image acquisition device is strictly perpendicular to the plane of the rectangular working area 110 and the installation angle is correct, then the line connecting the centers of the two recovery funnels 130 should be strictly parallel to the horizontal reference side 111, i.e., the included angle should be zero. If the calculated included angle is not zero, it indicates that there is an installation posture error in the image acquisition device. The controller can compensate for subsequent deviation measurement results based on this included angle value, or directly issue a prompt on the user interface, requiring manual intervention to adjust the camera's installation angle. Through this verification step, systematic errors caused by camera installation deviations can be effectively eliminated, further improving the accuracy of substrate alignment.

[0077] Example 5: Adaptation to different substrate types and threshold self-adaptation

[0078] The method and system of this invention can flexibly adapt to substrates of different shapes and can dynamically adjust the accuracy threshold according to process requirements. This embodiment describes the specific implementation methods for rectangular substrates and circular substrates, as well as the implementation method of threshold self-adaptation.

[0079] For a rectangular substrate, as described in this invention, its substrate reference edge 11 can be any one of its edges. In the ideal alignment template, the geometric center 12 of the rectangular substrate is required to coincide with the geometric center 13 of the rectangular working area, and any edge of the substrate selected as the reference edge is parallel to the horizontal reference edge 111 of the rectangular working area 110.

[0080] For circular substrates, as described in this invention, they do not have natural edges as reference directions, therefore a preset reference direction is required. This reference direction can be defined as the preset notch direction of the substrate edge (e.g., a notch on a wafer) or the preset mark direction of the substrate surface. In the ideal alignment template, the center of the circular substrate needs to coincide with the geometric center 13 of the rectangular working area, and the periphery of the circle needs to maintain a preset gap with the boundary of the rectangular working area 110 to ensure that the substrate is completely located within the working area. During adjustment, the robot first visually identifies the notch or mark, rotates it to the preset reference direction, and then performs a translation operation to make the center of the circle coincide with the target center.

[0081] Regarding threshold adaptation, the preset translation threshold and rotation threshold are set separately according to the substrate size and process requirements, and different adaptation strategies are adopted for the two:

[0082] Translation threshold: Positively correlated with substrate feature size (rectangle side length or circle diameter). It can be calculated using a linear scaling formula: Translation threshold = Baseline translation threshold × (Substrate feature size / Standard size)

[0083] The reference translation threshold and standard size are determined based on typical process experience. For example, if the reference translation threshold is 1.0 mm when the standard size is 100 mm, then the translation threshold is adaptively set to 0.5 mm for a 50 mm substrate and 1.5 mm for a 150 mm substrate.

[0084] Rotation threshold: This is independent of substrate size and is determined solely by the process requirements for angular alignment accuracy. It is typically set to a fixed value, such as 0.5°. If the process is particularly sensitive to rotational deviations, it can be reduced to 0.2°; if requirements are less stringent, it can be increased to 1.0°. Linear scaling with substrate size is not recommended because the linear displacement effect of angular deviations is already reflected in translational deviations.

[0085] Alternatively, a pre-defined size-threshold mapping table can be used to store both translation and rotation thresholds, for example:

[0086]

[0087] This adaptive mechanism is automatically loaded at the start of each alignment process, thereby ensuring alignment accuracy while avoiding unnecessary over-adjustment.

[0088] Finally, the following points should be noted: First, in the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installation", "connection", and "linkage" should be interpreted broadly, and can be mechanical or electrical connections, or internal connections between two components, or direct connections. "Up", "down", "left", "right", etc. are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may change.

[0089] Secondly: The accompanying drawings of the embodiments disclosed in this invention only involve the structures involved in the embodiments disclosed in this invention. Other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of this invention can be combined with each other.

[0090] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for automatic substrate alignment based on an asymmetric developing tank, characterized in that: Includes the following steps: Step 1: Providing a developing tank: A developing tank is provided, the top view of which consists of a rectangular working area and a right-angled trapezoidal area; the rectangular working area and the right-angled trapezoidal area have different colors; at least two recovery funnels protruding from the bottom surface of the developing tank are provided on the hypotenuse side of the right-angled trapezoidal area; Step 2: Install the image acquisition device: Install the image acquisition device above the rectangular work area so that its field of view covers the entire developing tank; Step 3: Camera installation posture self-verification: Acquire an empty image of the developing tank, identify the centers of the at least two recovery funnels, calculate the angle between the line connecting their centers and the horizontal reference side of the rectangular working area, and if the angle exceeds the preset range, perform error compensation or issue an adjustment prompt. Step 4: Establish the ideal alignment template: Define the target pose of the substrate relative to the rectangular work area; Step 5: Acquire a top view image: Acquire a top view image of the substrate placed in the developing tank; Step 6: Segment the region and extract the contour: Segment the rectangular working area and the right-angled trapezoidal area based on the different colors, and extract the current substrate contour and substrate reference edge; Step 7: Calculate translation and rotation deviations: Calculate the translation and rotation deviations of the current substrate relative to the ideal aligned template; Step 8: Substrate Placement Verification: Detect whether the edge of the substrate obstructs the recycling funnel; if the obstruction area exceeds a preset threshold, the substrate placement is deemed to have failed, an alarm signal is issued and the placement process is terminated; otherwise, continue with the subsequent steps. Step 9: Deviance meets the standard: Adaptively set translation and rotation thresholds according to the substrate size; then determine whether the translation deviation is less than the preset translation threshold and whether the rotation deviation is less than the preset rotation threshold; if yes, the alignment is successful and the process ends; if no, control the robot to adjust the substrate pose according to the deviation, and then return to step 5.

2. The automatic substrate alignment method based on an asymmetric developing tank according to claim 1, characterized in that: In the step of using the line connecting the centers of the recycling funnels to perform self-calibration of the camera installation attitude, when there are two or more funnels, the line connecting the centers of the two funnels that are furthest apart is selected first.

3. The method for automatic substrate alignment based on an asymmetric developing tank according to claim 1, characterized in that: The ideal alignment template is defined as follows: the geometric center of the substrate coincides with the geometric center of the rectangular working area, and the reference edge of the substrate is parallel to the horizontal reference edge of the rectangular working area; the translation deviation is the Euclidean distance between the geometric center of the substrate and the geometric center of the rectangular working area in the image coordinate system, and the rotation deviation is the angle between the reference edge of the substrate and the horizontal reference edge of the rectangular working area.

4. The method for automatic substrate alignment based on an asymmetric developing tank according to claim 1, characterized in that: When the robotic arm adjusts its posture, if the edge of the substrate exceeds the boundary of the rectangular working area, it will first translate and pull back before rotating; otherwise, it will prioritize rotation adjustment before translation adjustment.

5. The automatic substrate alignment method based on an asymmetric developing tank according to claim 1, characterized in that: The right-angled trapezoidal region has its right-angled legs parallel to the horizontal line. The longer and shorter parallel sides of the right-angled trapezoidal region are both perpendicular to the horizontal line, with the shorter parallel side located on the side away from the rectangular working area and the longer parallel side coinciding with one side of the rectangular working area.

6. The automatic substrate alignment method based on an asymmetric developing tank according to claim 1, characterized in that: The preset translation threshold is adaptively set in a positive correlation with the substrate feature size, while the preset rotation threshold is a fixed value.

7. The automatic substrate alignment method based on an asymmetric developing tank according to claim 1, characterized in that: The substrate is rectangular, and the reference edge of the substrate is any one of its sides.

8. The automatic substrate alignment method based on an asymmetric developing tank according to claim 1, characterized in that: The substrate is circular, and its reference direction is the preset missing edge direction or the marked point direction; in the ideal alignment template, the center of the circle coincides with the center of the rectangular working area, and the periphery of the circle maintains a preset gap with the boundary of the rectangular working area.

9. The automatic substrate alignment method based on an asymmetric developing tank according to claim 1, characterized in that: The substrate placement verification step further includes: determining whether the substrate has warped or tilted by the change in the relative projection position between the substrate edge and the funnel protrusion.

10. An automatic substrate alignment system based on an asymmetric developing tank, characterized in that, include: An asymmetric developing tank, whose top view outline consists of a rectangular working area and a right-angled trapezoidal area, wherein the rectangular working area and the right-angled trapezoidal area have different colors; The right-angled trapezoidal area is provided with at least two recycling funnels protruding from the bottom surface of the tank on the hypotenuse side; An image acquisition device is installed directly above the rectangular working area, and its field of view covers the entire developing tank. A robotic arm is used to pick up, place, and adjust substrates; The controller is configured to perform the method of any one of claims 1 to 9.

Images