Multi-degree-of-freedom calibration method of wafer transmission manipulator

Abstract

The invention provides a multi-degree-of-freedom calibration method for a wafer transmission manipulator, which comprises the following steps of: S100, detecting a moving track of a radial telescopic shaft of a mechanical arm, and calibrating the straightness of the radial telescopic shaft; s200, the levelness of a turnover shaft of the mechanical arm is detected, and the levelness of the turnover shaft is calibrated; s300, the mechanical arm is connected with the radial alignment tool; s400, the mechanical arm controls the radial alignment tool to move into the wafer conveying box, and coarse positioning of the radial alignment tool and the reference wafer is achieved; s500, the positions of a radial telescopic shaft and a horizontal moving shaft of the mechanical arm are calibrated, and the position coordinates of the radial telescopic shaft and the horizontal moving shaft of the mechanical arm are calibrated; and S600, the reference lifting height of the lifting shaft of the mechanical arm is detected. The invention provides a multi-degree-of-freedom calibration method of a wafer transmission manipulator, and aims to solve the problems that an error accumulation effect is easy to occur and the transmission precision is influenced because the existing calibration method cannot realize multi-degree-of-freedom systematic calibration.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor manufacturing, and more specifically, relates to a multi-degree-of-freedom calibration method for a wafer transfer manipulator. Background Art

[0002] In the field of semiconductor manufacturing, the chemical mechanical polishing (CMP) process is a key link in wafer surface treatment. As a core device among them, the performance of the wafer transfer manipulator directly affects the smooth progress of the process. The wafer transfer manipulator needs to achieve precise grasping, transfer, and placement of wafers through a multi-degree-of-freedom structure such as a radial telescopic shaft, a lifting shaft, a horizontal moving shaft, and a turning shaft. Its positioning accuracy is a decisive factor in whether the wafer can be successfully picked up and placed at each module station. However, due to the light-impermeable characteristics of the FOUP (Front Opening Unified Pod), it is difficult to observe the specific landing points of the radial telescopic shaft and the horizontal moving shaft of the robotic arm during operation. Once the point deviation exceeds the allowable range, it is extremely easy to cause the wafer edge to rub against the positioning posts, or to cause collisions due to misalignment with the station, ultimately resulting in transfer failure, wafer breakage, or even equipment downtime.

[0003] In the prior art, the calibration method of the wafer transfer manipulator has significant technical limitations, mainly manifested in the lack of high-precision standardized design in the calibration process, over-reliance on the subjective experience judgment of operators, resulting in strong randomness and poor repeatability of calibration operations. Not only does it require repeated debugging and consume a large amount of time, but also the calibration efficiency is low. More critically, the prior art fails to establish a systematic calibration specification for multi-degree-of-freedom manipulators, and the error influence mechanism between each motion axis is not fully considered. For example, the straightness error of the radial telescopic shaft will be transmitted through the motion chain and affect the positioning accuracy of the horizontal moving shaft. This error accumulation effect ultimately causes the actual position of the end effector of the manipulator to deviate from the target position. When the positioning error of the horizontal moving shaft exceeds the allowable range of ±0.5 mm, it is extremely easy to cause process anomalies such as wafer grasping failure and placement position deviation, and in severe cases, it will cause the wafer edge to collide with the positioning mechanism, resulting in an increase in the fragmentation rate. This problem of insufficient calibration accuracy not only increases the equipment maintenance cost, but also seriously restricts the stability of the CMP process and the product yield rate, becoming a technical bottleneck restricting the improvement of semiconductor manufacturing accuracy. Summary of the Invention

[0004] The purpose of the present invention is to provide a multi-degree-of-freedom calibration method for a wafer transfer manipulator, aiming to solve the problem that the existing calibration method cannot achieve systematic calibration of multiple degrees of freedom, resulting in an easy occurrence of error accumulation effect and affecting the transfer accuracy.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] Provide a multi-degree-of-freedom calibration method for a wafer transfer manipulator, including:

[0007] S100. Detect the movement trajectory of the radial telescopic shaft of the robotic arm, and calibrate the straightness of the radial telescopic shaft of the robotic arm;

[0008] S200. Use a level to detect the levelness of the turning shaft of the robotic arm, and calibrate the levelness of the turning shaft of the robotic arm;

[0009] S300. Connect the robotic arm that has completed straightness calibration and levelness calibration to a radial alignment tooling. The radial alignment tooling is a transparent component, and one end of the radial alignment tooling facing away from the robotic arm has a detection surface adapted to the outer peripheral surface of the reference wafer;

[0010] S400. The robotic arm controls the radial alignment tooling to move into the wafer transfer cassette and approach the reference wafer to achieve rough positioning with the reference wafer;

[0011] S500. Use the radial alignment tooling to respectively calibrate the positions of the radial telescopic shaft and the horizontal movement shaft of the robotic arm. When the detection surface of the radial alignment tooling is completely attached to the reference wafer, respectively calibrate the position coordinates of the radial telescopic shaft and the horizontal movement shaft of the robotic arm;

[0012] S600. Detect the reference lifting height of the lifting shaft of the robotic arm, and calibrate the reference lifting height so that the reference lifting height of the robotic arm is consistent with the thickness of the bearing groove of the wafer transfer cassette.

[0013] In a possible implementation manner, the S100 specifically includes:

[0014] S110. Set a laser rangefinder on one side of the robotic arm along a first path, and the first path is perpendicular to the preset telescopic path of the robotic arm;

[0015] S120. Set a plurality of reflection targets at intervals along the preset telescopic path on the robotic arm. As the robotic arm telescopes, the laser rangefinder successively detects the distances between the laser rangefinder and the plurality of reflection targets;

[0016] S130. Compare the actual distance values detected by the laser rangefinder with the theoretical distance values when the robotic arm moves along the preset telescopic path one by one, and analyze the deviation between the actual telescopic path and the preset telescopic path of the robotic arm;

[0017] S140. Adjust and control the driving mechanism and / or transmission mechanism for the radial telescoping of the robotic arm according to the deviation between the actual telescopic path and the preset telescopic path of the robotic arm, so that the actual telescopic path of the robotic arm is consistent with the preset telescopic path.

[0018] In a possible implementation, the S200 includes:

[0019] S210. Set a spirit level on the robotic arm to ensure that the spirit level fits perfectly with the robotic arm.

[0020] S220. Detect the levelness of the robotic arm. If the levelness of the robotic arm deviates from the preset levelness, adjust the robotic arm until the levelness of the robotic arm reaches the preset levelness.

[0021] In a possible implementation, the S500 includes:

[0022] S510. After the rough positioning of the robotic arm and the reference wafer, an adjustment gap is formed between the detection surface and the outer peripheral surface of the reference wafer.

[0023] S520. Adjust the position of the robotic arm to further reduce the adjustment gap, and while reducing the adjustment gap, ensure that the distances between the regions of the detection surface and the outer peripheral surface of the reference wafer are consistent.

[0024] S530. Move the robotic arm along the axial direction of the radial expansion and contraction axis. When the adjustment gap ≤ 0.02 mm, stop moving the robotic arm, and respectively calibrate the position coordinates of the radial expansion and contraction axis and the horizontal movement axis of the robotic arm at this time.

[0025] In a possible implementation, in the S520, a plurality of distance detectors are embedded in the radial alignment tooling. The plurality of distance detectors are sequentially and spaced apart along the inner peripheral surface of the detection surface. The distance detectors and the detection surface are located on the same curved surface. The distance detectors are used to detect the distance from the outer peripheral surface of the reference wafer and are communicatively connected to the robotic arm.

[0026] In a possible implementation, the S600 includes:

[0027] S610. Place reference wafers in the bottom carrier slot and the top carrier slot of the wafer transfer cassette respectively.

[0028] S620. Install a laser sensor on the robotic arm. The light projected by the laser sensor is perpendicular to the central axis of the wafer transfer cassette.

[0029] S630. Control the robotic arm to move uniformly from bottom to top in the wafer transfer cassette along the direction parallel to the central axis of the wafer transfer cassette until the robotic arm moves to the top of the wafer transfer cassette.

[0030] S640. Record the change in laser intensity of the laser sensor during the movement of the robotic arm, determine the time difference Δt between the occurrences of two light intensity valleys, and calculate the spacing between adjacent carrier slots based on the time difference Δt. Use the spacing between adjacent carrier slots as the reference value for the lifting height of the lifting axis of the robotic arm.

[0031] In a possible implementation, the S620 includes:

[0032] S621. Install the emitting end of the laser sensor on the robotic arm, and install the receiving end of the laser sensor along the axial direction of the radial telescopic shaft. The laser emitted by the emitting end passes through the central axis of the wafer transfer cassette and is received by the receiving end.

[0033] S622. Adjust the height of the laser sensor so that the light intensity amplifier shows the maximum value, i.e., the peak, when there is no occlusion, and shows the minimum value, i.e., the valley, when the laser of the laser sensor is blocked by the reference wafer.

[0034] In a possible implementation, the S640 includes:

[0035] S641. During the process of the robotic arm moving upward at a constant speed along the direction parallel to the central axis of the wafer transfer cassette, collect the laser intensity change curve in real time through the light intensity display.

[0036] S642. Record the time points t1 and t2 of each valley according to the laser intensity change curve.

[0037] S643. According to the time difference Δt = t2 - t1 between the two valleys, and in combination with the lifting speed V of the robotic arm, calculate the spacing L between the bottom carrier slot and the top carrier slot in the wafer transfer cassette t , L t = V × Δt;

[0038] S644. Calculate the spacing between adjacent carrier slots. There are n carrier slots in the wafer transfer cassette, and the spacing between adjacent carrier slots is L s , so L s = L t / (n - 1);

[0039] S645. Use a camera to photograph the rising process of the laser sensor to verify the correspondence between the light intensity signal and the physical position of the laser sensor.

[0040] In a possible implementation, the S640 further includes:

[0041] S646. Repeat the S641 - S645 multiple times;

[0042] S647. Take the average value of all the obtained Ls. s Calculate the average value.

[0043] In a possible implementation, the radial alignment tooling includes a connecting plate and flanges distributed on both sides of the connecting plate perpendicular to the radial telescopic shaft, and further includes a detection plate disposed on the end face of the connecting plate along the radial telescopic shaft. The detection plate forms the detection surface, and the detection plate is docked with the flanges.

[0044] The beneficial effects of the multi-degree-of-freedom calibration method for the wafer transfer manipulator provided by the present invention are as follows: Compared with the prior art, by calibrating the radial telescopic shaft, the flipping shaft, and the lifting shaft of the robotic arm step by step, establishing a systematic calibration process and introducing a standardized calibration tooling, the technical problems of strong subjectivity and poor repeatability in the calibration process in the prior art are effectively solved. The present invention adopts a preprocessing step that combines straightness calibration and levelness calibration to eliminate the inherent errors of each axis system of the robotic arm from the source of the motion chain; through a transparent radial alignment tooling, a dual verification mechanism of visual-assisted rough positioning and precise contact calibration with the reference wafer is realized, significantly improving the positioning accuracy of the radial telescopic shaft and the horizontal movement shaft. This solution breakthroughly constructs a multi-degree-of-freedom error decoupling compensation model. Through the synergistic effect of the lifting shaft height calibration and the radial-horizontal axis linkage calibration, the error accumulation effect is successfully suppressed, and the comprehensive positioning error of the end effector is reduced. This solution greatly shortens the single calibration time, improves the calibration qualification rate, effectively avoids the problems of wafer grasping failure and edge collision caused by positioning deviation, and reduces the wafer fragmentation rate in the CMP process. Description of the Drawings

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0046] Figure 1 It is a schematic structural diagram of the multi-degree-of-freedom calibration method for the wafer transfer manipulator provided by the embodiment of the present invention;

[0047] Figure 2 It is a schematic diagram of the mechanism of the radial alignment tooling adopted by the embodiment of the present invention;

[0048] Figure 3 It is a schematic diagram of S100 in the embodiment of the present invention;

[0049] Figure 4 It is a schematic diagram of S500 in the embodiment of the present invention;

[0050] Figure 5 Structural schematic diagram of the wafer transfer box adopted in the embodiment of the present invention;

[0051] Figure 6 Schematic diagram of S600 in the embodiment of the present invention.

[0052] In the figure: 1, radial alignment tooling; 101, connecting plate; 102, flanging; 103, detection surface; 2, robotic arm; 3, laser rangefinder; 4, reference wafer; 5, wafer transfer box; 6, laser sensor; 601, transmitting end; 602, receiving end. Specific embodiments

[0053] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0054] In the claims, the description and the above-mentioned drawings of the present invention, unless otherwise clearly defined, when using terms such as "first", "second" or "third", etc., are used to distinguish different objects and not to describe a specific order. Unless otherwise specified, the remaining orientation terms, such as "vertical", "clockwise", "counterclockwise", etc., indicate the orientation and position relationship based on the orientation and position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, so it should not be understood as limiting the specific protection scope of the present invention. In the claims, the description and the above-mentioned drawings of the present invention, unless otherwise clearly defined, when using terms such as "fixed connection" or "fixedly connected", should be understood in a broad sense, that is, any connection method without displacement relationship and relative rotation relationship between the two, that is, including non-detachable fixed connection, detachable fixed connection, being integrated as one body, and being fixedly connected through other devices or elements. In the claims, the description and the above-mentioned drawings of the present invention, when using terms such as "including", "having" and their variants, are intended to mean "including but not limited to".

[0055] Please refer to Figures 1 to 6 , and now a multi-degree-of-freedom calibration method for a wafer transfer manipulator provided by the present invention will be described. The multi-degree-of-freedom calibration method for a wafer transfer manipulator includes:

[0056] S100. Detect the movement trajectory of the radial telescopic shaft of the robotic arm 2, and perform straightness calibration on the radial telescopic shaft of the robotic arm 2;

[0057] S200. Detect the levelness of the flip shaft of the robotic arm 2 using a level, and perform levelness calibration on the flip shaft of the robotic arm 2;

[0058] S300. Connect the robotic arm 2 that has completed straightness calibration and level calibration to the radial alignment tooling 1. The radial alignment tooling 1 is a transparent component, and one end of the radial alignment tooling 1 facing away from the robotic arm 2 has a detection surface 103 adapted to the outer peripheral surface of the reference wafer 4;

[0059] S400. The robotic arm 2 controls the radial alignment tooling 1 to move into the wafer transfer cassette 5 and approach the reference wafer 4 to achieve rough positioning with the reference wafer 4;

[0060] S500. Use the radial alignment tooling 1 to calibrate the positions of the radial telescopic shaft and the horizontal movement shaft of the robotic arm 2 respectively. When the detection surface 103 of the radial alignment tooling 1 is fully attached to the reference wafer 4, calibrate the position coordinates of the radial telescopic shaft and the horizontal movement shaft of the robotic arm 2 respectively;

[0061] S600. Detect the reference lifting height of the lifting shaft of the robotic arm 2 and calibrate the reference lifting height so that the reference lifting height of the robotic arm 2 is consistent with the thickness of the bearing groove of the wafer transfer cassette 5.

[0062] Compared with the prior art, the multi-degree-of-freedom calibration method of the wafer transfer robotic arm provided by the present invention effectively solves the technical problems of strong subjectivity and poor repeatability in the prior art calibration process by step-by-step calibration of the radial telescopic shaft, the flipping shaft, and the lifting shaft of the robotic arm 2, establishing a systematic calibration process and introducing a standardized calibration tooling. The present invention adopts a preprocessing step of combining straightness calibration and level calibration to eliminate the inherent errors of each axis system of the robotic arm 2 from the source of the motion chain; through the transparent radial alignment tooling 1, a dual verification mechanism of visual-assisted rough positioning and precise contact calibration with the reference wafer 4 is realized, significantly improving the positioning accuracy of the radial telescopic shaft and the horizontal movement shaft. This solution breakthroughly constructs a multi-degree-of-freedom error decoupling compensation model, and through the synergistic effect of the lifting shaft height calibration and the radial-horizontal axis linkage calibration, the error accumulation effect is successfully suppressed, reducing the comprehensive positioning error of the end effector. This solution greatly shortens the single calibration time, improves the calibration qualification rate, effectively avoids the problems of wafer grasping failure and edge collision caused by positioning deviation, and reduces the wafer fragmentation rate of the CMP process.

[0063] In some embodiments, referring to Figure 3 , S100 specifically includes:

[0064] S110. Set a laser rangefinder 3 on one side of the robotic arm 2 along a first path, and the first path is perpendicular to the preset telescopic path of the robotic arm 2;

[0065] S120. Set a plurality of reflection targets at intervals along the preset telescopic path on the robotic arm 2. As the robotic arm 2 expands and contracts, the laser rangefinder 3 successively detects the distances between the laser rangefinder 3 and the plurality of reflection targets;

[0066] S130, comparing the actual spacing value detected by the laser rangefinder 3 with the theoretical spacing value when the robot arm 2 moves along the preset telescopic path, and analyzing the deviation between the actual telescopic path of the robot arm 2 and the preset telescopic path;

[0067] S140, adjusting and controlling the driving mechanism and / or transmission mechanism for radial extension and retraction of the robotic arm 2 according to the deviation between the actual extension and retraction path of the robotic arm 2 and the preset extension and retraction path, so that the actual extension and retraction path of the robotic arm 2 is consistent with the preset extension and retraction path.

[0068] This embodiment adopts the solution of collaborative detection of laser rangefinder 3 and reflective target. By arranging the laser rangefinder 3 perpendicular to the telescopic path of the robot arm 2 and the reflective target array arranged at intervals, high-precision dynamic monitoring of the radial telescopic motion trajectory of the robot arm 2 is achieved. This solution can capture the deviation between the actual telescopic path of the robot arm 2 and the preset telescopic path in real time, and accurately identify the distribution law and maximum deviation position of the straightness error by comparing the actual spacing of multiple detection points with the theoretical value. Based on the drive / transmission mechanism compensation adjustment mechanism established in this way, key influencing factors such as guide rail assembly error and lead screw pitch cumulative error can be corrected in a targeted manner, so that the straightness error of the radial telescopic axis of the robot arm 2 is controlled within ±0.1mm. This non-contact measurement method not only avoids the secondary error caused by contact measurement of traditional mechanical measuring tools, but also establishes a complete motion trajectory error model through multi-point sampling, laying a precise benchmark foundation for subsequent multi-degree-of-freedom collaborative calibration, while improving the efficiency of straightness calibration, and significantly reducing the risk of wafer transmission deflection caused by radial telescopic path deviation.

[0069] In some embodiments, S200 includes:

[0070] S210, setting a level on the robotic arm 2 to ensure that the level is completely in contact with the robotic arm 2;

[0071] S220, detecting the levelness of the robotic arm 2, and if the levelness of the robotic arm 2 deviates from the preset levelness, adjusting the robotic arm 2 until the levelness of the robotic arm 2 reaches the preset levelness.

[0072] This solution adopts the scheme of directly attaching a high-precision level to the robotic arm 2, achieving rapid and precise calibration of the horizontal degree of the flipping axis. By rigidly connecting the level to the robotic arm 2, this method eliminates the installation errors caused by traditional indirect measurement methods, improving the detection accuracy of the horizontal degree. When the detected horizontal degree deviates from the preset value, the system can immediately trigger an automatic adjustment mechanism to correct the attitude of the robotic arm 2 in real time through closed-loop control, ensuring that the horizontal degree error of the flipping axis at any angle does not exceed ±0.01°. This level of accuracy fully meets the stringent requirements for flatness in wafer transfer. This solution not only solves the problems of low efficiency and poor repeatability in traditional manual leveling, but also shortens the horizontal calibration time. More importantly, it fundamentally eliminates the wafer flatness deviation caused by the tilt of the robotic arm 2, controlling the planar deflection angle during wafer transfer within 0.1°, effectively preventing the risk of collision between the wafer and the edge of the transfer mechanism, and laying a reliable reference plane for subsequent precise positioning.

[0073] In some embodiments, refer to Figure 4 , S500 includes:

[0074] S510. After the rough positioning of the robotic arm 2 and the reference wafer 4, an adjustment gap is formed between the detection surface 103 and the outer peripheral surface of the reference wafer 4;

[0075] S520. Adjust the position of the robotic arm 2 to further narrow the adjustment gap, and ensure that the distances between the various regions of the detection surface 103 and the outer peripheral surface of the reference wafer 4 are consistent while narrowing the adjustment gap;

[0076] S530. Move the robotic arm 2 along the axial direction of the radial telescopic axis. When the adjustment gap ≤ 0.02 mm, stop moving the robotic arm 2, and calibrate the position coordinates of the radial telescopic axis and the horizontal movement axis of the robotic arm 2 at this time respectively.

[0077] The gap control type precision calibration method proposed in this embodiment realizes the ultimate calibration of the spatial position of the robotic arm 2 through the sub-micron level adjustment gap (≤ 0.02 mm) formed between the detection surface 103 and the outer peripheral surface of the reference wafer 4. This solution adopts a progressive positioning strategy of "coarse first and then fine". After rough positioning, by real-time monitoring the consistency of the gaps between the various regions of the detection surface 103 and the wafer, it intelligently adjusts the multi-axis movement of the robotic arm 2, not only compensating for the residual straightness error of the radial telescopic axis, but also synchronously correcting the deflection error of the horizontal movement axis. When the gap reaches the critical value of 0.02 mm, the system automatically records the coordinates of each movement axis, establishes an accurate zero reference, and improves the repeat positioning accuracy of the end effector of the robotic arm 2. This calibration method based on the critical state of physical contact has stronger anti-interference ability than traditional optical positioning methods and improves the calibration stability.

[0078] Optionally, after completing the rough positioning, the adjustment gap ≤ 0.02 mm can be determined by using a feeler gauge for detection.

[0079] In some embodiments, in S520, a plurality of distance detectors are embedded in the radial alignment tooling 1. The plurality of distance detectors are sequentially and spaced apart along the inner circumferential surface of the detection surface 103. The distance detectors and the detection surface 103 are located on the same curved surface. The distance detectors are used to detect the distance from the outer circumferential surface of the reference wafer 4 and are communicatively connected to the robotic arm 2.

[0080] This embodiment adopts an advanced calibration scheme of an embedded multi-sensor array. By integrating a high-precision distance detector array within the curved surface of the detection surface 103 of the radial alignment tooling 1, the distances between various regions of the detection surface 103 and the outer circumferential surface of the reference wafer 4 are made the same, thereby ensuring that the detection surface 103 can fully conform to the outer circumferential surface of the reference wafer 4 during the fine positioning stage. These equidistantly distributed distance detectors maintain a co-curved surface design with the detection surface 103, which not only avoids measurement interference caused by sensor protrusion but also can accurately capture the microscopic distance differences between various regions of the detection surface 103 and the outer circumferential surface of the wafer. When the robotic arm 2 makes a position adjustment, multi-sensor data is real-time fed back to the control system through a high-speed communication link to form a closed-loop adjustment, reducing the gap consistency error between the detection surface 103 and the reference wafer. This distributed sensing network improves the calibration accuracy compared to the single-point detection method, especially solves the problem of edge fitting of large-sized wafers due to curvature, and at the same time improves the response speed of the calibration process.

[0081] In some embodiments, please refer to Figures 5 to 6 , S600 includes:

[0082] S610, place the reference wafer 4 in the bottom and top carrier slots of the wafer transfer cassette 5 respectively;

[0083] S620, install a laser sensor 6 on the robotic arm 2, and the light projected by the laser sensor 6 is perpendicular to the central axis of the wafer transfer cassette 5;

[0084] S630, control the robotic arm 2 to move uniformly from bottom to top in the wafer transfer cassette 5 along a direction parallel to the central axis of the wafer transfer cassette 5 until the robotic arm 2 moves to the top of the wafer transfer cassette 5;

[0085] S640, record the change in the laser intensity of the laser sensor 6 during the movement of the robotic arm 2, determine the time difference Δt between the occurrences of two light intensity valleys, and calculate the distance between two adjacent carrier slots based on the time difference Δt, and use the distance between two adjacent carrier slots as the reference value for the lifting height of the lifting axis of the robotic arm 2.

[0086] This solution adopts laser sensing dynamic scanning technology, and realizes the automatic calibration of the lifting axis height by measuring the distance between the reference wafers 4 in the wafer transfer cassette 5. This method installs a laser sensor 6 perpendicular to the central axis of the transfer cassette on the robotic arm 2. By using the change in the reflected light intensity of the laser on the surface of adjacent reference wafers 4 during the uniform lifting process, the time difference Δt between two valley signals is accurately captured. Combining the known lifting speed of the robotic arm 2, the distance between the carrier slots can be calculated. This non-contact measurement avoids the mechanical wear problem of traditional gauge calibration, is particularly suitable for precise measurement in a narrow space, and improves the height calibration efficiency. By establishing the lifting value based on the actual distance between the carrier slots, the influence of machining tolerances and installation errors is eliminated, enabling the lifting positioning accuracy of the robotic arm 2 to reach ±0.01 mm, ensuring that the clearance between the wafer and the carrier slot during transmission is controlled within the preset range, effectively preventing the risk of wafer jamming or slipping caused by height deviation, and providing a reliable height reference guarantee for high-density wafer stacking transmission.

[0087] Optionally, in S610, ensure that the edge of the reference wafer 4 is fully fitted with the carrier slot without tilt.

[0088] In some embodiments, please refer to Figure 6 , S620 includes:

[0089] S621. Install the emitting end 601 of the laser sensor 6 on the robotic arm 2, and install the receiving end 602 of the laser sensor 6 along the axial direction of the radial expansion shaft. The laser emitted by the emitting end 601 passes through the central axis of the wafer transfer cassette 5 and is received by the receiving end 602;

[0090] S622. Adjust the height of the laser sensor 6 so that the light intensity amplifier displays the maximum value, i.e., the peak, when there is no occlusion, and displays the minimum value, i.e., the valley, when the reference wafer 4 occludes the laser of the laser sensor 6.

[0091] This solution installs the laser emitting end 601 and the receiving end 602 on both sides of the radial expansion shaft of the robotic arm 2 respectively, constructing a precise optical path system that penetrates the central axis of the wafer transfer cassette 5. Utilize the occlusion effect of the reference wafer 4 on the laser beam to generate a significant light intensity change signal (peak-valley). By precisely adjusting the height of the laser, the light intensity amplifier outputs the maximum value when there is no occlusion, ensuring that the system operates at the best sensitivity state. This symmetric optical path arrangement makes the laser beam strictly perpendicular to the central axis of the transfer cassette, eliminating the cosine error caused by traditional oblique incidence measurement and reducing the angular deviation of height detection. Combined with a high-resolution light intensity detection circuit, the system can accurately identify the change in the edge position of the reference wafer 4, improving the detection accuracy compared with the traditional contact height measurement method. This non-contact measurement method not only avoids mechanical wear, but also can adapt to the high-speed lifting and scanning requirements, shortening the single complete calibration time, and providing a fast and accurate height reference calibration solution for the semiconductor production line.

[0092] Optionally, a U-shaped mounting bracket is installed on the robotic arm 2. The mounting bracket has a receiving area for accommodating the wafer transfer cassette 5, so that one mounting area of the mounting bracket is located on the opening side of the wafer transfer cassette 5, and the other mounting area is located on the other side of the wafer transfer cassette 5 corresponding to the opening side. The transmitting end 601 is installed in one mounting area, and the receiving end 602 is installed in the other mounting area, so that the receiving end 602 can receive the laser emitted by the transmitting end 601.

[0093] In some embodiments, S640 includes:

[0094] S641, during the process of the robotic arm 2 moving upward at a constant speed along the direction parallel to the central axis of the wafer transfer cassette 5, the change curve of the laser intensity is collected in real time through the light intensity display;

[0095] S642, record the time points t1 and t2 of each trough according to the change curve of the laser intensity;

[0096] S643, according to the time difference Δt = t2 - t1 between two troughs, combined with the lifting speed V of the robotic arm 2, calculate the distance L between the bottom bearing groove and the top bearing groove in the wafer transfer cassette 5 t , L t = V × Δt;

[0097] S644, calculate the distance between two adjacent bearing grooves. There are n bearing grooves in the wafer transfer cassette 5, and the distance between two adjacent bearing grooves is L s , so L s = L t / (n - 1);

[0098] S645, use a camera to shoot the rising process of the laser sensor 6 to verify the correspondence between the light intensity signal and the physical position of the laser sensor 6.

[0099] In this embodiment, by combining high-precision laser ranging and vision calibration technologies, sub-micron-level measurement of the wafer bearing groove spacing is achieved. This method uses the change curve of the laser intensity collected during the uniform lifting process to accurately capture the time difference Δt between two troughs, and combines the constant speed V of the robotic arm 2 to calculate the total distance L t , reducing the measurement uncertainty of the adjacent groove distance L s . Introducing a high-speed camera for optical path-position synchronization calibration, a mapping relationship between the light intensity signal and the physical position is constructed, effectively identifying and eliminating signal anomalies caused by mechanical vibration or optical interference, and improving the measurement reliability. This spatio-temporal synchronous closed-loop detection mechanism not only solves the cumulative error problem caused by traditional segmented measurement, but also can automatically compensate for the influence of temperature drift on the laser wavelength, and is especially suitable for rapid calibration of full-size wafer transfer cassettes 5.

[0100] In some embodiments, S640 further includes:

[0101] S646. Repeating S641 - S645 multiple times;

[0102] S647. Taking the average value of all obtained L s for the average value calculation.

[0103] The multi - repeated measurement and averaging algorithm introduced in this solution, by repeating the laser scanning measurement process multiple times (recommended 5 - 10 times) and taking the average value of all obtained adjacent carrier slot spacings L s effectively suppresses random errors and single - measurement deviations, and improves the repeatability accuracy of spacing measurement. This statistical processing method can automatically filter out instantaneous vibration interferences (such as motor stepping fluctuations, transmission clearances, etc.) during the movement of the robotic arm 2, eliminate accidental errors, and reduce the standard deviation of the final calibration result. Combining with the high - precision laser ranging and vision calibration technologies in the early stage, this solution constructs a triple - guarantee system of "measurement - calibration - statistical optimization", which not only ensures the ultra - high reliability of the calibration of the lifting axis reference height, but also can intelligently diagnose potential abnormalities of the mechanical system (such as guide rail wear or belt slack) through the dispersion degree of multiple measurement data, providing data support for preventive maintenance.

[0104] In some embodiments, referring to Figure 2 , the radial alignment tooling 1 includes a connecting plate 101 and flanges 102 distributed on both sides of the connecting plate 101 along a direction perpendicular to the radial telescopic shaft, and further includes a detection plate arranged on the end face of the connecting plate 101 along the radial telescopic shaft. The detection plate forms a detection surface 103, and the detection plate is docked with the flange 102.

[0105] The connecting plate 101, as the core connecting component, provides a basis for the stable connection between the tooling and the robotic arm 2, ensuring the stability of the coordinated movement of the tooling and the robotic arm 2 during the calibration process. The flanges 102 distributed on both sides of the connecting plate 101 along a direction perpendicular to the radial telescopic shaft can provide guiding and limiting functions during the movement of the robotic arm 2, effectively preventing the tooling from deviating in non - target directions, and improving the accuracy and reliability of calibration. The detection plate arranged on the end face of the connecting plate 101 along the radial telescopic shaft forms a detection surface 103 that fits the outer peripheral surface of the reference wafer 4. The structural design of the docking of the detection plate with the flange 102 enables the tooling to accurately fit the reference wafer 4, facilitating quick rough positioning with the reference wafer 4, and at the same time providing an accurate reference plane for the position calibration of the radial telescopic shaft and the horizontal movement shaft, overcoming the calibration problem caused by the non - light - transmissive property of the front - opening wafer transfer cassette 5, and greatly improving the efficiency and accuracy of the multi - degree - of - freedom calibration of the robotic arm 2, ensuring the precise operation of the wafer transfer manipulator.

[0106] Optionally, the flange 102 is perpendicular to the connecting plate 101.

[0107] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A multi-degree-of-freedom calibration method for a wafer transfer manipulator, characterized in that Including: S100. Detect the movement trajectory of the radial telescopic shaft of the robotic arm, and calibrate the straightness of the radial telescopic shaft of the robotic arm; S200. Use a spirit level to detect the levelness of the tilting shaft of the robotic arm, and calibrate the levelness of the tilting shaft of the robotic arm; S300. Connect the robotic arm that has completed the straightness calibration and the levelness calibration to a radial alignment tooling. The radial alignment tooling is a transparent component, and one end of the radial alignment tooling facing away from the robotic arm has a detection surface adapted to the outer peripheral surface of the reference wafer; S400. The robotic arm controls the radial alignment tooling to move into the wafer transfer cassette and approach the reference wafer to achieve rough positioning with the reference wafer; S500. Use the radial alignment tooling to respectively calibrate the positions of the radial telescopic shaft and the horizontal movement shaft of the robotic arm. When the detection surface of the radial alignment tooling is completely attached to the reference wafer, calibrate the position coordinates of the radial telescopic shaft and the horizontal movement shaft of the robotic arm respectively; S600. Detect the reference lifting height of the lifting shaft of the robotic arm, and calibrate the reference lifting height to make the reference lifting height of the robotic arm consistent with the thickness of the bearing groove of the wafer transfer cassette.

2. The multi-degree-of-freedom calibration method of the wafer transfer manipulator according to claim 1, wherein, The S100 specifically includes: S110. Set a laser rangefinder on one side of the robotic arm along a first path, and the first path is perpendicular to the preset telescopic path of the robotic arm; S120. Set a plurality of reflection targets at intervals along the preset telescopic path on the robotic arm. As the robotic arm extends and retracts, the laser rangefinder detects the distances between the laser rangefinder and the plurality of reflection targets one by one; S130. Compare the actual distance values detected by the laser rangefinder with the theoretical distance values when the robotic arm moves along the preset telescopic path one by one, and analyze the deviation between the actual telescopic path and the preset telescopic path of the robotic arm; S140. Adjust and control the driving mechanism and / or transmission mechanism for the radial extension and retraction of the robotic arm according to the deviation between the actual telescopic path and the preset telescopic path of the robotic arm, so that the actual telescopic path of the robotic arm is consistent with the preset telescopic path.

3. The multi-degree-of-freedom calibration method of the wafer transfer manipulator according to claim 1, characterized in that, The S200 includes: S210. Set a spirit level on the robotic arm to ensure that the spirit level is completely attached to the robotic arm; S220. Detect the levelness of the robotic arm. If the levelness of the robotic arm deviates from the preset levelness, adjust the robotic arm until the levelness of the robotic arm reaches the preset levelness.

4. The multi-degree-of-freedom calibration method of the wafer transfer manipulator according to claim 1, characterized in that The S500 includes: S510. After the rough positioning of the robotic arm and the reference wafer, an adjustment gap is formed between the detection surface and the outer peripheral surface of the reference wafer; S520. Adjust the position of the robotic arm to further reduce the adjustment gap, and while reducing the adjustment gap, ensure that the distances between each area of the detection surface and the outer peripheral surface of the reference wafer are consistent; S530. Move the robotic arm along the axial direction of the radial telescopic shaft. When the adjustment gap ≤ 0.02 mm, stop moving the robotic arm, and respectively calibrate the position coordinates of the radial telescopic shaft and the horizontal movement shaft of the robotic arm at this time.

5. The multi-degree-of-freedom calibration method of the wafer transfer manipulator according to claim 4, characterized in that In the S520, a plurality of distance detectors are embedded in the radial alignment tooling. The plurality of distance detectors are sequentially and spaced apart along the inner circumferential surface of the detection surface. The distance detectors and the detection surface are located on the same curved surface. The distance detectors are used to detect the distance from the outer circumferential surface of the reference wafer and are communicatively connected to the robotic arm.

6. The multi-degree-of-freedom calibration method for the wafer transfer manipulator according to claim 1, wherein, The S600 includes: S610. Place reference wafers in the bottom carrier slot and the top carrier slot of the wafer transfer cassette respectively; S620. Install a laser sensor on the robotic arm, and the light projected by the laser sensor is perpendicular to the central axis of the wafer transfer cassette; S630. Control the robotic arm to move uniformly from bottom to top in the wafer transfer cassette along the direction parallel to the central axis of the wafer transfer cassette until the robotic arm moves to the top of the wafer transfer cassette; S640. Record the change in the laser intensity of the laser sensor during the movement of the robotic arm, determine the time difference Δt between the occurrences of two light intensity valleys, and calculate the distance between two adjacent carrier slots according to the time difference Δt, and use the distance between two adjacent carrier slots as the reference value for the lifting height of the lifting axis of the robotic arm.

7. The multi-degree-of-freedom calibration method of the wafer transfer manipulator according to claim 6, characterized in that, The S620 includes: S621. Install the emitting end of the laser sensor on the robotic arm, and install the receiving end of the laser sensor along the axial direction of the radial expansion shaft. The laser emitted by the emitting end passes through the central axis of the wafer transfer cassette and is received by the receiving end; S622. Adjust the height of the laser sensor so that the light intensity amplifier displays the maximum value, i.e., the peak, when there is no occlusion, and displays the minimum value, i.e., the valley, when the reference wafer occludes the laser of the laser sensor.

8. The multi-degree-of-freedom calibration method of the wafer transfer manipulator according to claim 6, wherein The S640 includes: S641. During the process of the robotic arm moving uniformly from bottom to top along the direction parallel to the central axis of the wafer transfer cassette, collect the laser intensity change curve in real time through the light intensity display; S642. Record the time points t1 and t2 of each valley according to the laser intensity change curve; S643. Calculate the distance L between the bottom carrier slot and the top carrier slot in the wafer transfer cassette based on the time difference Δt = t2 - t1 between two wave troughs and in combination with the lifting speed V of the robotic arm t , L t = V × Δt; S644. Calculate the distance between two adjacent carrier slots. There are n carrier slots in the wafer transfer cassette, and the distance between two adjacent carrier slots is L s , so L s = L t / (n - 1); S645. Use a camera to photograph the ascending process of the laser sensor to verify the correspondence between the light intensity signal and the physical position of the laser sensor.

9. The multi-degree-of-freedom calibration method of the wafer transfer manipulator according to claim 8, characterized in that, The S640 further includes: S646. Repeat the S641 - the S645 multiple times; S647. Calculate the average value of all the obtained Ls. s Calculate the average value.

10. The multi-degree-of-freedom calibration method of the wafer transfer manipulator according to claim 1, characterized in that, The radial alignment tooling includes a connecting plate and flanges distributed on both sides of the connecting plate perpendicular to the radial expansion shaft. It also includes a detection plate provided on the end face of the connecting plate along the radial expansion shaft. The detection plate forms the detection surface, and the detection plate is butted against the flange.

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