Anti-collision wafer picking method and system capable of identifying wafer warping, storage medium

Abstract

The application provides a wafer warping identifiable anti-collision wafer taking method and system and a storage medium, wherein the method comprises the following steps: setting a profile collector on the vertical surface of an aligner wafer; collecting wafer profile point data during the rotation of the aligner wafer, so as to determine the center position of the wafer and the eccentric distance of the center position from the rotation center of the wafer, and the direction angle between the projection position of the profile collector on the wafer surface and the center of the wafer and the rotation center of the wafer; determining the theoretical distance from the rotation center of the wafer to the wafer profile in the ideal case of no wafer warping according to the eccentric distance, the direction angle and the known wafer radius; determining the height difference between the ideal and actual postures of the wafer according to the theoretical distance and the actual distance from the wafer profile to the rotation center of the wafer, so as to judge the wafer warping degree and correspondingly adjust the wafer taking height of the robot. In this way, the robot can be prevented from interfering with the wafer during wafer taking.

Description

Technical Field

[0001] This invention relates to wafer picking technology, and more particularly to a collision-resistant wafer picking method and system that can identify wafer warping, as well as a storage medium. Background Technology

[0002] With semiconductor manufacturing entering the era of 300mm / 450mm large-size wafers, wafer warpage has become a key factor affecting the accuracy of photolithography alignment. According to SEMI standards, the allowable warpage for 300mm wafers should be ≤50μm, but in actual processes (such as 3D NAND multilayer stacking), warpage often reaches 100-200μm.

[0003] In semiconductor manufacturing, the collaborative operation of wafer aligners and cleanroom robots has a significant impact on production efficiency. To optimize production cycle time and reduce overall uptime, process engineers typically set the robot's UP (rise) and DOWN (fall) positions to precisely meet the minimum safe distance for placing the wafer onto the aligner.

[0004] However, this parameter setting that pursues maximum efficiency may bring potential quality risks. For example, when handling wafers with warpage, especially when the lowest point of warpage is the initial pick-up position of the robot arm, the actual gap between the robot arm's end effector and the wafer surface is insufficient, which can easily lead to mechanical interference during the pick-up process. This can result in scratches on the wafer surface or even wafer breakage and damage. Such problems are particularly significant in the automated transfer of ultra-thin wafers (thickness <100μm) and large-size wafers (300mm and above). Summary of the Invention

[0005] Therefore, the main objective of this invention is to provide a collision-resistant wafer picking method and system, and a storage medium capable of identifying wafer warping, so as to prevent interference between the robotic arm and the wafer during wafer picking.

[0006] To achieve the above objectives, according to one aspect of the present invention, a collision-avoidance wafer removal method capable of identifying wafer warpage is provided, comprising the steps of:

[0007] A profile acquisition device is set on the vertical plane of the aligner wafer. During the wafer rotation process of the aligner, wafer profile point data is collected to determine the position of the wafer center and its eccentric distance from the wafer rotation center, as well as the angle between the projection position of the profile acquisition device on the wafer surface and the direction of the wafer center and the wafer rotation center.

[0008] Based on the eccentricity, directional angle, and known wafer radius, determine the theoretical distance from the wafer rotation center to the wafer profile under ideal conditions where the wafer is warp-free;

[0009] Based on the theoretical distance and the actual distance from the wafer outline to the wafer rotation center, the height difference between the ideal and actual wafer orientation is determined to judge the degree of wafer warpage and adjust the robot's wafer picking height accordingly.

[0010] In a possible preferred embodiment, the step of calculating the eccentricity distance includes:

[0011] Extract the coordinates of all wafer contour points and calculate the initial coordinates of the wafer center using the least squares method;

[0012] Using the wafer rotation center as the origin, calculate the eccentricity distance between the wafer center and the wafer rotation center based on the initial coordinates of the wafer center.

[0013] In a possible preferred embodiment, the step of calculating the included direction angle includes:

[0014] Calculate the actual distance between each wafer profile point and the wafer rotation center. ;

[0015] Calculate the angle between directions :

[0016]

[0017] in For eccentric distance, Given the radius of the wafer.

[0018] In a possible preferred embodiment, the step of calculating the theoretical distance includes:

[0019] Calculate the theoretical distance :

[0020]

[0021] in For eccentric distance, Given the wafer radius, The angle between the directions is denoted by .

[0022] In a possible preferred embodiment, the step of determining the degree of wafer warpage includes:

[0023] Calculate the average height difference ratio between the ideal and actual orientations of all wafers at each wafer profile point;

[0024] When the average height difference ratio is within the collision threshold range, the current wafer warpage is considered to be within the adjustable range.

[0025] In a possible preferred embodiment, the step of calculating the average height difference ratio includes:

[0026] Remove wafer outline points from the Notch / Flat region in the wafer outline point data, and assign adjustment weights to wafer outline points in the Notch / Flat symmetrical region.

[0027] Calculate the average of the height difference ratios between the ideal and actual orientations of all wafers at the remaining wafer profile points;

[0028] When the average height difference ratio is within the collision threshold range, the current wafer warpage is considered to be within the adjustable range.

[0029] In a possible preferred embodiment, the step of adjusting the robot's slice-picking height includes:

[0030] judge:

[0031] like Then adjust the robot's image picking height as follows:

[0032]

[0033] in This is the initial image picking height for the robot. The height of the alignment platform relative to the robot. To preset the safe buffer distance for picking up and placing films, This represents the maximum height difference between the ideal and actual state of the wafer.

[0034] In a possible preferred embodiment, the step of adjusting the robot's slice-picking height further includes:

[0035] judge:

[0036] like Then adjust the robot's image picking height as follows:

[0037] .

[0038] To achieve the above objectives, corresponding to the above method examples, according to another aspect of the present invention, a collision-avoidance wafer picking system capable of identifying wafer warping is also provided, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the system implements the steps of any of the above-described collision-avoidance wafer picking methods capable of identifying wafer warping.

[0039] To achieve the above objectives, in accordance with the above method examples, according to another aspect of the present invention, a computer-readable storage medium is also provided, the computer-readable storage medium storing a computer program, wherein when the computer program is executed, it implements the steps of the anti-collision wafer removal method for identifying wafer warping as described above.

[0040] The collision-resistant wafer picking method and system, along with the storage medium provided by this invention, which can identify wafer warping, cleverly utilizes wafer alignment and contour acquisition devices to extract wafer contour point data. This data is used to calculate the height difference between the ideal and actual wafer orientation, thereby enabling dynamic quantitative assessment of the degree of wafer warping. This allows the robot to automatically adjust the picking height based on the actual deformation of the wafer, achieving a closed-loop control of detection-decision-execution. This ensures wafer picking is completed without collision risk, preventing interference between the robotic arm and the wafer during picking. It fundamentally solves industry problems such as wafer breakage and mechanical collisions caused by the inability to accurately identify or compensate for wafer warping in semiconductor manufacturing, providing crucial assurance for automated handling of ultra-thin / large-size wafers in advanced process technologies. Attached Figure Description

[0041] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0042] Figure 1 This is a schematic diagram of the steps of the anti-collision wafer removal method for identifying wafer warping according to the present invention;

[0043] Figure 2 This is a schematic diagram of the overall logic flow of the anti-collision wafer picking method that can identify wafer warping according to the present invention;

[0044] Figure 3 This is a schematic diagram showing the spatial relationship and orientation of related calculation parameters between the aligner, CCD, and wafer in the anti-collision wafer picking method for identifying wafer warping according to the present invention.

[0045] Figure 4 This is a schematic diagram of the weight allocation of the flat region of the wafer in the anti-collision wafer picking method that can identify wafer warping according to the present invention.

[0046] Figure 5 This is a schematic diagram of the anti-collision wafer picking system for identifying wafer warping according to the present invention. Detailed Implementation

[0047] To enable those skilled in the art to better understand the technical solutions of the present invention, the specific technical solutions of the present invention will be clearly and completely described below in conjunction with embodiments, so as to help those skilled in the art further understand the present invention. Obviously, the embodiments described in this application are merely some embodiments of the present invention, and not all embodiments. It should be noted that, for those skilled in the art, the embodiments and features in the embodiments of this application can be combined with each other without departing from the concept of the present invention and without conflict. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the disclosure and protection scope of the present invention.

[0048] Furthermore, the terms "first," "second," "S1," "S2," etc., used in the specification, claims, and drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such features can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those described herein. At the same time, the stages described in each step are not necessarily to be implemented in the same step; it should be understood that the implementation order of the contents of each step stage can be adjusted and interchanged without violating the inventive concept, so that embodiments of the invention described herein can be implemented in orders other than those described herein. Additionally, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. Unless otherwise expressly specified and limited, the terms "set," "arrange," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or a connection within two elements. Those skilled in the art can understand the specific meaning of the above terms in this case based on the specific circumstances and in conjunction with existing technology.

[0049] To prevent interference between the robotic arm and the wafer during wafer picking, this invention proposes a collision-avoidance wafer picking method that can identify wafer warping. The concept is to dynamically and quantitatively assess the degree of wafer warping by calculating the height difference between the wafer surface contour position and the ideal reference plane. At the same time, through data feedback, the robot can automatically determine whether Z-axis position compensation is needed based on the actual deformation of the wafer, so as to complete wafer picking without the risk of collision.

[0050] Specifically, such as Figures 1 to 3 As shown, the anti-collision wafer removal method for identifying wafer warpage provided by the present invention includes the following steps:

[0051] Step S1: Set a profile acquisition device on the vertical plane of the aligner wafer. During the wafer rotation process of the aligner, acquire wafer profile point data to determine the position of the wafer center and its eccentric distance from the wafer rotation center, as well as the angle between the projection position of the profile acquisition device on the wafer surface and the direction of the wafer center and the wafer rotation center.

[0052] Specifically, to identify the height difference between the actual wafer orientation and the ideal non-warped planar orientation, this example preferably uses wafer contour point data to illustrate the implementation process. To acquire this wafer contour point data, the contour acquisition device can be a LiDAR, a charge-coupled device (CCD), etc. In this example, a CCD is used as an example. Figure 3 As shown, the CCD is preferably positioned in the direction perpendicular to the wafer rotation surface to ensure that the wafer edge is within its acquisition range when the wafer aligner drives the wafer to rotate.

[0053] As the wafer rotates one revolution, based on the CCD's preset sampling frequency, all contour points along the wafer's circumference can be captured in 360°. .

[0054] Furthermore, to determine the location of the wafer center and its eccentricity relative to the wafer rotation center, the calculation steps in this example include:

[0055] Step S11: Extract the coordinates of all wafer contour points and calculate the initial coordinates of the wafer center using the least squares method. , ).

[0056] The example calculation process is as follows:

[0057] ∑ =X1 (Calculates the sum of the x-coordinates of all points)

[0058] ∑ =Y1 (Calculates the sum of the y-coordinates of all points)

[0059] ∑ =X² (Calculates the sum of the squares of the x-coordinates of all points)

[0060] ∑ =Y2 (Calculates the sum of the squares of the y-coordinates of all points)

[0061] ∑ =X3 (Calculates the sum of the cubes of the x-coordinates of all points)

[0062] ∑ =Y3 (Calculates the sum of the cubes of the y-coordinates of all points)

[0063] ∑ =X1Y1 (Calculates the sum of the x*y products of all points)

[0064] ∑ =X1Y2 (Calculate the sum of the x*y² products of all points)

[0065] ∑ =X2Y1 (Calculate the sum of the products of x² and y at all points)

[0066] N = Number of contour points

[0067] C=

[0068] D=

[0069] E=

[0070] G=

[0071] H=

[0072] a=

[0073] b=

[0074] final( , )for: , .

[0075] Step S12: Using the wafer rotation center as the origin, calculate the eccentricity distance between the wafer center and the wafer rotation center based on the initial coordinates of the wafer center.

[0076] Specifically, with the wafer rotation center as the origin (0,0), the eccentricity distance between the wafer center and the wafer rotation center is:

[0077] = .

[0078] Furthermore, in order to calculate the directional angle, the calculation steps in this example include:

[0079] Step S13: First, calculate the contour points of each wafer. The actual distance from the wafer rotation center ;

[0080] Step S14: Based on the known wafer radius and the eccentricity distance calculated in step S12 above. The direction angle can be calculated. :

[0081] .

[0082] Step S2: Based on the eccentricity, directional angle, and known wafer radius, determine the theoretical distance from the wafer rotation center to the wafer profile under ideal conditions where the wafer is warp-free.

[0083] Among them, the theoretical distance from the center of rotation to the wafer profile point under ideal, warp-free conditions is... It should be:

[0084]

[0085] in , These are the previously obtained or known eccentricity distance, known wafer radius, and orientation angle parameters, respectively.

[0086] Step S3 determines the height difference between the ideal and actual wafer orientation based on the theoretical distance and the actual distance from the wafer outline to the wafer rotation center, in order to judge the degree of wafer warping and adjust the robot's wafer picking height accordingly.

[0087] Specifically, the example steps for determining the degree of wafer warpage include:

[0088] Step S31: Calculate the contour points of each wafer. At this point, all wafer ideals With reality Attitude difference :

[0089]

[0090] Based on this, the average height difference ratio Z can be calculated, and the maximum height difference under this wafer orientation can also be obtained. This is used for subsequent robot image retrieval height adjustment judgment.

[0091] On the other hand, reference Figure 4 As shown, considering the presence of notches / flat edges in the Notch / Flat region of the wafer, in order to improve calculation accuracy, in an optional embodiment, the calculation step of the average height difference ratio may further include:

[0092] Step S311: Remove Notch / Flat regions from wafer profile data. The wafer profile points (optionally including data from the 3mm area surrounding the wafer profile points in the Notch / Flat region, and data from the Notch / Flat symmetrical region) are also included. The wafer profile points are assigned adjustment weights.

[0093] In this example, considering that warping generally exhibits symmetry, the Notch / Flat symmetrical region is considered. Double weighting is applied, however, those skilled in the art can adjust it according to the specific circumstances of the wafer structure, and this invention does not impose any limitations.

[0094] Step S312: Calculate the average height difference ratio between the ideal and actual orientations of all wafers at the remaining wafer profile points. :

[0095]

[0096]

[0097] in: This represents the total number of wafer outline points. A piecewise function with different weights is assigned to each region. For a single wafer profile acquisition point, The height difference between a warped wafer and a horizontal wafer at a given point. This is the theoretical distance from the center of rotation to the wafer profile point under ideal, warp-free conditions.

[0098] Step S32: When the average height difference ratio Z is determined to be within the collision threshold... When the range is defined, it is assumed that the current wafer warpage is within the adjustable range.

[0099] Among them, the collision threshold In industrial settings with high tolerance, this value can generally be set to 0.05–0.2. However, this example does not impose any limitations, and those skilled in the art can set different thresholds according to specific scenarios. Furthermore, when Z is higher than the threshold... If the warping is severe enough that adjusting the robot's pick-up height cannot ensure interference-free operation, the warped wafer can be discarded. Conversely, if the warping is less severe, the conditions for adjusting the robot's pick-up height are met.

[0100] Furthermore, as an example, the steps for adjusting the robot's slice-picking height include:

[0101] Step S33: Based on the known height of the alignment platform relative to the robot... Preset safe buffer distance for picking up and placing pieces and the maximum height difference between the ideal and actual state of the wafer. Adjust the robot's initial film-picking height to a non-interference film-picking height.

[0102] For example, to determine:

[0103] like Then adjust the robot's image picking height as follows:

[0104]

[0105] in Example setting: 300~400 Those skilled in the art can make adjustments according to the actual situation, and the present invention does not impose any limitations.

[0106] Furthermore, in an optional implementation, the step of adjusting the robot's slice-picking height further includes:

[0107] Step S34

[0108] judge:

[0109] like Then adjust the robot's image picking height as follows:

[0110] .

[0111] As can be seen from the above examples, the anti-collision wafer picking method for identifying wafer warping of the present invention cleverly designs a three-dimensional topography reconstruction scheme to convert the two-dimensional contour point data of the wafer into a three-dimensional topography, thereby realizing the assessment of the degree of wafer warping by calculating the height difference between the current orientation of the wafer and the ideal horizontal reference plane of the wafer. This has created a new direction for evaluating the degree of wafer warping.

[0112] Furthermore, to improve measurement accuracy, this solution automatically eliminates interference data from Notch / Flat contour points and their surrounding areas. Based on the symmetrical characteristics of wafer warpage, it innovatively introduces a symmetrical region weighted compensation mechanism to ensure the reliability of the calculation results. This approach accurately achieves dynamic quantitative assessment of the degree of wafer warpage, enabling the robot to automatically adjust the picking height according to the actual deformation of the wafer. This achieves a fully closed-loop control of detection-decision-execution, ensuring wafer picking is completed without collision risks and preventing interference between the robotic arm and the wafer during wafer picking. This fundamentally solves industry problems such as wafer breakage and mechanical collisions caused by the inability to accurately identify wafer warpage or incorrect compensation during semiconductor manufacturing.

[0113] On the other hand, referring to the above method example, see Figure 5 As shown, the present invention also provides a collision-avoidance wafer retrieval system capable of identifying wafer warpage, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the system implements the steps of any of the collision-avoidance wafer retrieval methods for identifying wafer warpage described in the above examples.

[0114] On the other hand, corresponding to the above method examples, the present invention also provides a computer-readable storage medium storing a computer program, wherein when the computer program is executed, it implements the steps of the anti-collision wafer removal method for identifying wafer warping as described in any of the above examples.

[0115] In summary, the proposed method, system, and storage medium for identifying wafer warpage and preventing collisions, provided by this invention, cleverly utilizes wafer alignment and contour acquisition devices to extract wafer contour point data. This data is used to calculate the height difference between the ideal and actual wafer orientation, enabling dynamic quantitative assessment of the degree of wafer warpage. The robot can automatically adjust its picking height based on the actual deformation of the wafer, thus achieving a closed-loop control of detection, decision-making, and execution. This ensures wafer picking is completed without collision risk, preventing interference between the robotic arm and the wafer during picking. It fundamentally solves industry problems such as wafer breakage and mechanical collisions caused by inaccurate identification or incorrect compensation of wafer warpage in semiconductor manufacturing, providing crucial assurance for automated handling of ultra-thin / large-size wafers in advanced process technologies.

[0116] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The present invention is limited only by the claims and their full scope and equivalents. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the protection scope of the invention.

[0117] Those skilled in the art will understand that, besides implementing the system, apparatus, unit, and its modules provided by this invention in purely computer-readable program code, the same program can be implemented in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system, apparatus, and its modules provided by this invention can be considered a hardware component, and the modules included therein for implementing various programs can also be considered structures within the hardware component; alternatively, modules for implementing various functions can be considered both software programs implementing the method and structures within the hardware component.

[0118] Furthermore, all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware. This program is stored in a storage medium and includes several instructions to cause a microcontroller, chip, or processor to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0119] Furthermore, various different implementations of the present invention can be combined arbitrarily, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed in the present invention.

Claims

1.A wafer warpage identifiable anti-collision wafer picking method, comprising steps of: The profile collector is arranged on the vertical surface of the aligner wafer, and the coordinates of the wafer profile points are collected during the rotation of the aligner wafer, and the initial coordinates of the wafer center are calculated by the least square method; and the eccentric distance between the wafer center and the wafer rotation center is calculated according to the initial coordinates of the wafer center with the wafer rotation center as the origin ​ Calculating the real distance of each wafer profile point to the wafer rotation center , according to the known wafer radius Calculating the directional angle : ； Theoretical distance from the center of rotation to the wafer profile in the ideal case of a wafer without warpage , ； determining the height difference between the ideal and actual poses of the wafer according to the theoretical distance and the actual distance from the wafer profile to the wafer rotation center, judging the wafer warpage degree, and adjusting the robot wafer picking height accordingly. 2.The wafer warpage identifiable anti-collision wafer picking method of claim 1, wherein the step of judging the wafer warpage degree comprises: calculating the average of the height difference ratio between the ideal and actual poses of the wafer at each wafer profile point; when the average of the height difference ratio is within the collision threshold range, it is considered that the current wafer warpage degree meets the adjustable range. 3.The wafer warpage identifiable anti-collision wafer picking method of claim 1, wherein the step of calculating the average of the height difference ratio comprises: excluding the wafer profile points in the Notch / Flat area of the wafer profile point data, and assigning an adjustment weight to the wafer profile points in the Notch / Flat symmetric area; calculating the average of the height difference ratio between the ideal and actual poses of the wafer at each wafer profile point; when the average of the height difference ratio is within the collision threshold range, it is considered that the current wafer warpage degree meets the adjustable range. 4.The wafer warpage identifiable anti-collision wafer picking method of claim 1, wherein the step of adjusting the robot wafer picking height comprises: judging: If then adjust the robotic biopsy height to be: ； wherein is the initial picking height of the robot, is the height of the aligner rotating platform relative to the robot, is the preset picking and placing safety buffer distance, is the maximum height difference between the ideal and real attitude of the wafer. 5.The wafer warpage identifiable anti-collision wafer picking method of claim 4, wherein the step of adjusting the robot wafer picking height further comprises: judging: If then adjust the robotic biopsy height to be: 。 6. An anti-collision wafer picking system capable of identifying wafer warpage comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the system implements the steps of the wafer warpage identifiable anti-collision wafer picking method according to any one of claims 1 to 5. 7.A computer readable storage medium, storing a computer program, wherein when the computer program is executed, the steps of the wafer warpage identifiable anti-collision wafer picking method according to any one of claims 1 to 5 are implemented.

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