Wafer centering mechanism, wafer processing apparatus, and wafer centering control method

Abstract

The embodiment of the application provides a wafer centering mechanism, a wafer processing device and a wafer centering control method, and belongs to the technical field of semiconductor devices.The wafer centering mechanism comprises a unit main body platform (1), a device rack (2), a photoelectric sensor (3), a unit leveling assembly (4) and an electromagnetic sliding pin assembly (5).The wafer placing turntable (6) is installed on the unit main body platform (1).The unit main body platform (1) is provided with a radial sliding groove (11).The stop end (521) of the electromagnetic sliding pin assembly (5) slides along the radial sliding groove (11) to the center of the wafer placing turntable (6) under electromagnetic driving, drives the wafer to move, and aligns the center of the wafer with the center of the wafer placing turntable (6).The embodiment of the application saves the complex sensor and various complex mechanical structures, saves the production cost, improves the reliability and stability of the wafer processing device, realizes the leveling requirement of the wafer centering mechanism through the combination of simple parts, and has the advantages of simple structure, few parts, easy installation and the like.

Description

Technical Field

[0001] This application relates to the technical field of semiconductor devices, specifically to a wafer alignment mechanism, wafer processing equipment, and wafer alignment control method. Background Technology

[0002] In semiconductor manufacturing, wafer grinding and thinning are involved in both front-end and back-end processes. Currently, the most common method for wafer grinding and thinning is rotary grinding. The alignment of the wafer's center with the wafer-mounted frustum on the unit platform is crucial to grinding quality. Existing technologies for wafer alignment employ combinations such as a motor + gear pair + crank-slider or a cylinder + crank-slider, as illustrated in Chinese invention patent CN101043019A, entitled "Wafer Holding Mechanism." These methods require a large number of components and place high demands on design, installation, and control, thus reducing the system's manufacturability, reliability, and economy. To address these issues, existing technologies have not yet provided effective solutions and are no longer sufficient to meet requirements, necessitating improvement. Summary of the Invention

[0003] The main objective of this application is to provide a wafer alignment mechanism, wafer processing equipment, and wafer alignment control method to solve the problems of complex structure, insufficient automation and intelligence in the existing wafer alignment mechanisms and equipment.

[0004] According to one aspect of the embodiments of this application, a wafer alignment mechanism is provided, including a unit main platform, an equipment frame, and an electromagnetic sliding pin assembly, wherein: the unit main platform has a wafer placement frustum mounted on it, and the unit main platform has radial grooves arranged radially around the wafer placement frustum; the electromagnetic sliding pin assembly has a stop end at one end, which passes through the radial groove and abuts against the outer contour of the wafer, and slides along the radial groove towards the center of the wafer placement frustum under electromagnetic drive, so that the center of the wafer is aligned with the center of the wafer placement frustum.

[0005] According to at least one specific embodiment of the present application, the wafer placement platform is disposed at the center of the unit main platform, and the stop ends of multiple electromagnetic sliding pin assemblies surround to form a shape corresponding to the outer contour of the wafer. A photoelectric sensor is installed on one side of the wafer placement platform, and a wire groove is provided on one side of the photoelectric sensor.

[0006] According to at least one specific embodiment of the present application, an anti-adsorption groove is formed on the upper surface of the wafer placement frustum.

[0007] According to at least one specific embodiment of the present application, the electromagnetic sliding pin assembly is installed on the side of the unit main platform facing away from the wafer placement stage, and the end of the electromagnetic sliding pin assembly away from the wafer placement stage is the stop end, and the stop end is on the same side as the wafer placement stage.

[0008] According to at least one specific embodiment of the present application, the electromagnetic sliding pin assembly includes: a sliding pin cap, a sliding pin, a spring, a sliding pin housing, an electromagnetic coil, and a coil end cap. The sliding pin is L-shaped, with one end of the L-shaped sliding pin being a stop end and the other end being an abutment end. The abutment end abuts against one side of the spring, and an electromagnetic coil is provided on the other side of the spring. The electromagnetic coil is connected to an external power source and generates electromagnetic force through electromagnetic induction.

[0009] According to at least one specific embodiment of the present application, the sliding pin cap is fastened to the stop end by threads, the abutting end of the sliding pin extends into the cavity of the sliding pin housing and abuts against the spring, and an easily magnetizable material is provided on the sliding pin.

[0010] According to at least one specific embodiment of the present application, the portion of the sliding pin extending into the cavity is provided with a radially protruding flat key, a keyway corresponding to the flat key is provided on the inner wall of the sliding pin housing, an electromagnetic coil cavity for accommodating an electromagnetic coil is provided inside the sliding pin housing, the electromagnetic coil cavity is connected to the cavity, a spring end cap is provided at the opening of the cavity, and a coil end cap is provided at the opening of the electromagnetic coil cavity.

[0011] According to at least one specific embodiment of the present application, a unit leveling component is further included. The unit leveling component is disposed between the unit main platform and the equipment frame. The unit leveling component includes: fastening bolts, spring washers, flat washers, leveling columns, locking nuts, and lifting bolts, wherein:

[0012] The lifting bolt passes through the main platform of the unit and the equipment frame. A locking nut is installed between the lifting bolt and the equipment frame. A leveling column is set between the main platform of the unit and the equipment frame. A fastening bolt is set at the other end of the lifting bolt away from the locking nut. A spring washer and a flat washer are installed between the fastening bolt and the main platform of the unit.

[0013] According to another aspect of the embodiments of this application, a wafer processing apparatus is provided, wherein the wafer alignment mechanism is provided in the wafer processing apparatus.

[0014] According to another aspect of the embodiments of this application, a wafer alignment control method is provided for controlling the wafer alignment mechanism, comprising: determining the linear spring force of a spring based on the final displacement of an electromagnetic sliding pin assembly; determining the proportional relationship between the PWM duty cycle based on the linear relationship between the linear spring force and the electromagnetic force of an electromagnetic coil; generating a corresponding PWM signal by a wafer alignment control system; measuring the coil current of the electromagnetic coil in real time and feeding the measured coil current back to the wafer alignment control system; adjusting the corresponding PWM duty cycle according to the feedback coil current to synchronously control the magnitude of the electromagnetic force; controlling the electromagnetic sliding pin assembly to perform a motion of first acceleration and then deceleration by adjusting the PWM duty cycle during wafer alignment; and calculating the relationship between the magnitude of the electromagnetic force and the speed of the electromagnetic sliding pin assembly in real time to align the center of the wafer with the center of the wafer placement frustum.

[0015] The beneficial technical effects of the embodiments of this application are:

[0016] The wafer alignment mechanism utilizes an electromagnetic sliding pin assembly to control the current magnitude via electromagnetic drive, thereby controlling the displacement of the sliding pin cap (stop end). This eliminates the need for complex operations such as controlling motor rotation and other mechanisms. By controlling and monitoring the current through electromagnetic drive using an electromagnetic coil, the displacement of the sliding pin cap (stop end) can be calculated. This eliminates the need for angle measurement sensors and other equipment required in existing technologies, as well as motors, transmission mechanisms, cylinders, and hydraulic cylinders, significantly reducing production costs while improving the reliability and stability of the wafer processing equipment. This application embodiment also achieves the leveling requirement of the wafer alignment mechanism through a combination of simple parts such as fastening bolts, lifting bolts, and leveling columns, offering advantages such as simple structure, fewer parts, and easy installation. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the specific implementation methods or related technologies of this application, the accompanying drawings used in the description of the specific implementation methods or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some implementation methods of the embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a top view of the wafer alignment mechanism.

[0019] Figure 2 This is a side view of the wafer alignment mechanism.

[0020] Figure 3 This is a bottom view of the wafer alignment mechanism.

[0021] Figure 4 This is one of the perspective views of the wafer alignment mechanism.

[0022] Figure 5 This is the second perspective view of the wafer alignment mechanism.

[0023] Figure 5-I yes Figure 5 A magnified view of part A in the middle.

[0024] Figure 6 This is one of the exploded views of the wafer alignment mechanism.

[0025] Figure 7 This is the second exploded view of the wafer alignment mechanism.

[0026] Figure 8 This is a top view of the main platform of the unit.

[0027] Figure 9 This is a 3D view of the main platform of the unit.

[0028] Figure 10 This is a structural diagram (side view) of the electromagnetic sliding pin assembly.

[0029] Figure 11 This is a structural diagram (3D) of an electromagnetic sliding pin assembly.

[0030] Figure 12 This is a cross-sectional view of the electromagnetic sliding pin assembly.

[0031] Figure 13 This is one of the exploded views of an electromagnetic sliding pin assembly.

[0032] Figure 14 This is the second exploded view of the electromagnetic sliding pin assembly.

[0033] Figure 15 This is a structural diagram of the sliding pin housing.

[0034] Figure 16 This is a cross-sectional view of the sliding pin housing.

[0035] Figure 17 This is an exploded structural diagram of the unit leveling component.

[0036] Figure 17-I yes Figure 17 A magnified view of part B in the middle.

[0037] Figure 17-II yes Figure 17 A magnified view of part C in the middle.

[0038] Figure label:

[0039] Unit main platform 1, equipment frame 2, photoelectric sensor 3, unit leveling assembly 4, radial slide 11, wire groove 12, fastening bolt 41, spring washer 42, flat washer 43, leveling column 44, locking nut 45, lifting bolt 46, electromagnetic sliding pin assembly 5, sliding pin cap 51, sliding pin 52, stop end 521, abutment end 522, flat key 523, spring 53, sliding pin housing 54, keyway 541, pin body cavity 542, electromagnetic coil cavity 543, electromagnetic coil 55, coil end cover 56, spring end cover 57, wafer placement frustum 6, anti-adsorption groove 61, frustum center 62. Detailed Implementation

[0040] To enable those skilled in the art to better understand the embodiments of this application, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the implementation methods of the embodiments of this application, and not all of the implementation methods. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the protection scope of the embodiments of this application.

[0041] In the embodiments of this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are mainly for better describing the embodiments of this application and their implementation, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0042] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in the embodiments of this application based on the specific circumstances.

[0043] In semiconductor wafer fabrication, wafer alignment is a critical process involving specific alignment equipment and methods. Wafer alignment ensures precise positioning and alignment of the wafer throughout the fabrication process, guaranteeing accuracy and quality. Semiconductor wafer fabrication involves multiple steps, such as photolithography, etching, and thin-film deposition, each requiring the wafer to be in a precise position. The alignment unit aligns the wafer's center with the working center of the fabrication equipment, preventing misalignment during processing. For example, in photolithography, inaccurate alignment can cause the lithographic pattern to deviate from its intended position, preventing the proper formation of the chip's circuitry and ultimately affecting its functionality. Precise wafer alignment ensures consistent positioning accuracy across wafers in the same batch, guaranteeing high consistency in chip performance and quality. Inaccurate alignment can lead to variations in the depth and shape of etching during semiconductor processing, affecting the chip's electrical performance.

[0044] The principle of wafer alignment has already been mentioned in the background section of this specification. Existing technologies include optical alignment and mechanical alignment. However, optical alignment requires a high-resolution camera to capture alignment marks on the wafer, and then uses complex algorithms to calculate the distance and direction the wafer needs to move. This is costly and complex in terms of manufacturing process. Mechanical alignment primarily positions the wafer through physical contact. During mechanical alignment, complex and costly mechanical devices are used to fix the wafer or adjust the wafer processing equipment. Alignment mechanisms based on these two existing technologies also require a complex alignment control system. This system receives deviation signals from the alignment mark detection system, processes them, and sends control commands to the positioning and adjustment device. Based on the deviation angle and distance between the wafer alignment marks and the reference mark detected by the optical sensor, it calculates the number of adjustment steps and direction, and controls the motor's movement via a motor driver to achieve precise wafer alignment.

[0045] The wafer alignment mechanism and wafer alignment control method provided in this application differ from the prior art in that this application embodiment uses only simple machinery and relatively simple control methods to realize the wafer alignment operation of the wafer alignment mechanism, and the wafer alignment mechanism can be applied to various wafer processing equipment, and has a wide range of applications in the semiconductor processing field.

[0046] like Figures 1 to 9The wafer alignment mechanism shown in this embodiment of the application can be applied to various wafer processing equipment and implement corresponding wafer alignment control methods through the wafer processing equipment. The wafer alignment mechanism includes components such as a unit main platform 1, an equipment frame 2, a photoelectric sensor 3, a unit leveling assembly 4, and an electromagnetic sliding pin assembly 5. The unit main platform 1 is connected to the wafer processing equipment. A wafer placement frustum 6 is mounted on the unit main platform 1. The unit main platform 1 has radial grooves 11 arranged radially around the wafer placement frustum 6. One end of the electromagnetic sliding pin assembly 5 is a stop end 521, which passes through the radial groove 11 and abuts against the outer contour of the wafer. Under electromagnetic drive, the stop end 521 slides along the radial groove 11 towards the center of the wafer placement frustum 6, aligning the center of the wafer with the center of the wafer placement frustum 6.

[0047] Preferably, the wafer placement stage 6 is positioned at the center of the unit main platform 1, and the stop ends of multiple electromagnetic sliding pin assemblies 5 surround and form a shape corresponding to the outer contour of the wafer. A photoelectric sensor 3 is installed on one side of the wafer placement stage 6, and a groove 12 is formed on one side of the photoelectric sensor 3. The photoelectric sensor 3 can accurately detect whether the wafer is mounted on the unit main platform 1 by emitting a light beam and receiving the reflected light signal. The photoelectric sensor 3 can detect the photoelectric sensing signal to start or stop the wafer detection process. In some embodiments, the photoelectric sensor can also monitor the wafer position change in real time and feed back the detected signal to the wafer alignment control system. The wafer alignment control system adjusts the action of the wafer alignment mechanism according to the feedback signal to ensure accurate wafer alignment operation. Depending on the requirements of different working conditions and application scenarios, photoelectric sensors of different precision can be used. In some scenarios requiring high-precision detection, micron-level photoelectric sensors can be used to meet the high precision requirements in semiconductor manufacturing.

[0048] The function of the wire groove 12 is for wiring; that is, the cable (not shown in the figure) of the photoelectric sensor 3 passes through the wire groove 12 for arrangement. One end of the cable is connected to the photoelectric sensor 3, and the other end is connected to other equipment through the wire groove 12. The wafer placement platform 6 is placed at the center of the unit main platform 1, providing sufficient space for the radial slide groove 11. In this embodiment, to ensure the rigidity of the wafer alignment mechanism, a steel plate of a certain thickness is generally selected as the material. The wafer placement platform 6 is fixedly installed on the unit main platform 1, and its center is kept coincident with the center of the alignment unit. The sliding pin 52 in the electromagnetic sliding pin assembly 5 can slide along the radial slide groove 11 of the wafer alignment mechanism under the combined action of spring force and electromagnetic force. According to the correspondence between the sliding pin displacement, the linear spring compression, and the spring force, the movement of the sliding pin 52 can be achieved by adjusting the current and controlling the electromagnetic force. For example, five or more electromagnetic sliding pin assemblies can work together to center-align the wafer placed on the platform with the wafer placement platform 6, ensuring reliable and accurate subsequent processing.

[0049] Preferably, the electromagnetic sliding pin assembly 5 is installed on the side of the unit main platform 1 facing away from the wafer placement stage 6. The end of the electromagnetic sliding pin assembly 5 away from the wafer placement stage 6 is the stop end 521, and the stop end 521 is on the same side as the wafer placement stage 6. As can be seen from the attached drawings, the wafer placement stage 6 is on one side of the unit main platform 1, while most of the electromagnetic sliding pin assembly 5 is on the other side of the unit main platform 1. That is, the electromagnetic sliding pin assembly 5 and the wafer placement stage 6 are placed on different sides of the unit main platform 1. After the electromagnetic sliding pin assembly 5 puts the stop end 521 on the sliding pin cap 51, it passes through the radial sliding groove 11, so that the stop end 521 and the sliding pin cap 51 are on the same plane as the wafer placement stage 6 after passing through the radial sliding groove 11. Thus, the stop end of the electromagnetic sliding pin assembly 5 and the sliding pin cap 51 on it form a shape corresponding to the outer contour of the wafer. Since the shape formed by the enclosure corresponds to the outer contour of the wafer, as long as the movement direction of the sliding pins 52 of the multiple electromagnetic sliding pin assemblies 5 is towards the center of the wafer placement frustum 6, by reasonably controlling the electromagnetic driving force generated by the electromagnetic sliding pin assemblies 5 to make the multiple electromagnetic sliding pins move synchronously towards the center of the wafer placement frustum 6, it can be ensured that the center of the wafer can be aligned with the center 62 of the frustum of the wafer placement frustum 6, thus achieving wafer alignment.

[0050] As a further improvement to the embodiments of this application, such as Figure 5-IAs shown, an anti-adhesion groove 61 is formed on the upper surface of the wafer placement stage 6. The function of the anti-adhesion groove 61 is to prevent the wafer from sticking to the wafer placement stage 6 during processing. Because the wafer is relatively thin, when the wafer approaches a relatively smooth plane, the two can stick to the wafer placement stage 6 due to air pressure or electrostatic adsorption, making it difficult to rotate the wafer with a robotic arm. The presence of the anti-adhesion groove 61 balances the gas pressure between the upper and lower surfaces of the wafer, preventing the wafer from adhering to the wafer placement stage 6. In this embodiment, the anti-adhesion groove 61 is cross-shaped, but in other embodiments, the shape of the anti-adhesion groove 61 is not limited to a cross shape.

[0051] like Figures 10 to 16 As shown, the electromagnetic sliding pin assembly 5 includes a sliding pin cap 51, a sliding pin 52, a spring 53, a sliding pin housing 54, an electromagnetic coil 55, and a coil end cap 56. The sliding pin 52 is L-shaped with a bent portion. One end of the bent portion is connected to the stop end 521, and the other end is an abutment end 522, which abuts against one side of the spring 53. An electromagnetic coil 55 is located on the other side of the spring 53 and is connected to an external power source, generating electromagnetic force through electromagnetic induction. The sliding pin cap 51 is threaded onto the stop end 521. The abutment end 522 of the sliding pin 52 extends into the pin cavity 542 of the sliding pin housing 54. An easily magnetizable material, such as a magnet, is placed inside the sliding pin 52.

[0052] like Figure 14 As shown, preferably, a radially protruding flat key 523 is provided on the abutting end 522 of the sliding pin 52, and a keyway 541 corresponding to the flat key 523 is provided on the inner wall of the sliding pin housing 54. An electromagnetic coil cavity 543 for accommodating the electromagnetic coil 55 is provided at one end of the sliding pin housing 54 relative to the pin body cavity 542. The electromagnetic coil cavity 543 is connected to the pin body cavity 542. A spring end cap 57 is provided at the opening of the pin body cavity 542, and a coil end cap 56 is provided at the opening of the electromagnetic coil cavity 543. The external lead of the electromagnetic coil 55 can pass through the hole on the coil end cap 56 and be connected to an external power supply (not shown in the figure).

[0053] As can be seen from the attached drawings, the electromagnetic sliding pin assembly 5 has a sliding pin housing 54. Except for the sliding pin 52, most of the components are inside the sliding pin housing 54. The sliding pin housing 54 has two cavities: a pin body cavity 542 for accommodating the sliding pin 52 and an electromagnetic coil cavity 543 for accommodating the electromagnetic coil 55. The pin body cavity 542 and the electromagnetic coil cavity 543 are connected. In addition to the sliding pin 52, the pin body cavity 542 also includes a spring 53, which abuts against the sliding pin 52. When the electromagnetic coil 55 is energized, the sliding pins 52 in the multiple electromagnetic sliding pin assemblies 5 slide towards the electromagnetic coil 55 under the attraction of electromagnetic force. The stop ends 521 of the multiple electromagnetic sliding pin assemblies 5 surround the outside of the sliding pin housing 54 and abut against the outer contour of the wafer. The abutting ends 522 of the sliding pins 52 move inside the sliding pin housing 54, compressing the spring 53 and causing it to deform. That is, the abutting ends 522 of the sliding pins 52 are attracted by electromagnetic force and compress the spring 53, causing it to move. The stop ends 521 drive the wafer to move on the wafer placement frustum 6. Since the spring 53 is a linear spring, the relationship between its spring force and deformation is basically linear. After determining the spring stiffness, the displacement of the multiple electromagnetic sliding pin assemblies 5 can be synchronously controlled by controlling the current of the electromagnetic coil 55. Through the coordinated action of electromagnetic force and spring force, the center of the wafer is aligned with the center of the wafer placement frustum 6. Since the shape formed by the stop ends 521 corresponds to the outer contour of the wafer, and the linear spring has the same elastic deformation under the action of electromagnetic force, during the process of the stop ends 521 sliding towards the center 62 of the frustum 6 on the wafer, the multiple stop ends 521 continue to maintain the shape of the frustum center 62 as the center, and synchronously drive the wafer to align with the center 62 of the frustum.

[0054] Preferably, a strip-shaped keyway 541 is provided on the inner wall of the pin cavity 542, and a radially protruding flat key 523 is provided on the part of the sliding pin 52 that extends into the pin cavity 542. The flat key 523 is also strip-shaped, and the shape of the flat key 523 corresponds to and matches the shape of the keyway 541. When the sliding pin 52 moves along the radial groove 11, the flat key 523 moves in the keyway 541, which plays a role in positioning and constraining the movement of the sliding pin 52.

[0055] like Figure 17 , Figure 17-I and Figure 17-IIAs shown, as a further improvement to the embodiments of this application, the wafer alignment mechanism further includes a cell leveling assembly 4. The cell leveling assembly 4 passes through the cell main platform 1 and the equipment frame 2. The cell leveling assembly 4 includes: a fastening bolt 41, a spring washer 42, a flat washer 43, a leveling post 44, a locking nut 45, and a lifting bolt 46. The lifting bolt 46 passes through the cell main platform 1 and the equipment frame 2. A locking nut 45 is installed between the lifting bolt 46 and the equipment frame 2. A leveling post 44 is provided between the cell main platform 1 and the equipment frame 2. A fastening bolt 41 is provided at the other end of the lifting bolt 46 away from the locking nut 45. A spring washer 42 and a flat washer 43 are installed between the fastening bolt 41 and the cell main platform 1. By using multiple cell leveling assemblies 4 (e.g., three or more), the wafer can be kept in a horizontal position in the cell main platform 1.

[0056] This application also provides a wafer processing equipment, which is the main application scenario for wafer alignment mechanisms. The wafer processing equipment is equipped with a wafer alignment mechanism according to any specific embodiment of this application.

[0057] Based on the wafer alignment mechanism and wafer processing equipment, this application also provides a corresponding wafer alignment control method for controlling the wafer alignment mechanism in any specific embodiment of this application. The method includes the following steps:

[0058] Step S1, Electromagnetic force control parameter determination: Based on the final displacement of the electromagnetic sliding pin assembly 5, the linear spring force of spring 53 is determined. Based on the linear relationship between the linear spring force and the electromagnetic force of the electromagnetic coil 55, the proportional relationship between the PWM duty cycles is determined, and the wafer alignment control system generates the corresponding PWM signal. The determination of electromagnetic force control parameters is achieved through PWM signals. During the equipment debugging phase, the driving process of the PWM signal needs to be calibrated and recorded. Based on the calibration results, the variation law of the PWM duty cycle corresponding to different motion stages is determined, and the variation law is stored in the control program of the wafer processing equipment.

[0059] Step S2, Coil Current Measurement and Feedback Control: The coil current of the electromagnetic coil 55 is measured in real time, and the measured coil current is fed back to the wafer alignment control system. The corresponding PWM duty cycle is adjusted according to the feedback coil current to synchronously control the magnitude of the electromagnetic force.

[0060] Step S3, motion process control: During the wafer alignment process, the electromagnetic sliding pin assembly 5 is controlled to accelerate and then decelerate by adjusting the PWM duty cycle, so as to achieve precise displacement.

[0061] Step S4: Electromagnetic force and speed calculation: Calculate the relationship between the magnitude of the electromagnetic force and the speed of the electromagnetic sliding pin assembly 5 in real time until the center of the wafer is aligned with the center of the wafer placement frustum 6.

[0062] The wafer alignment control method provided in steps S1 to S4 achieves precise motion control of the wafer alignment mechanism to align the wafer center by precisely controlling electromagnetic force.

[0063] The linear spring force required for spring 53 is calculated based on the final displacement of the electromagnetic sliding pin assembly 5. The relationship between the linear spring force and the electromagnetic force is used to determine the proportional relationship between the PWM duty cycle and the electromagnetic force. Precise control of the electromagnetic force is achieved using the PWM signal. During equipment debugging, the PWM drive process is calibrated and recorded, storing the PWM duty cycle variation patterns corresponding to different motion stages. Real-time coil current measurement and feedback control are performed during the movement of the electromagnetic sliding pin assembly 5. The current of the electromagnetic coil 55 is measured in real time, and the measured value is fed back to the wafer alignment control system. For example, during wafer control, a closed-loop control algorithm can adjust the PWM duty cycle based on the feedback current value to synchronously control the magnitude of the electromagnetic force, ensuring its accuracy. Adjusting the PWM duty cycle controls the movement of the electromagnetic sliding pin assembly, causing it to move along a trajectory of first acceleration and then deceleration, avoiding wafer damage due to inertia. By repeatedly iterating through steps S1 to S4, the relationship between the electromagnetic force and velocity is calculated in real time until the center of the wafer is perfectly aligned with the center of the wafer placement frustum. In the technical solutions provided in steps S1 to S4, the wafer alignment control system can realize the wafer alignment control method through photoelectric sensors, wafer alignment mechanism and control algorithm. The photoelectric sensors detect the position, offset and alignment mark of the wafer. The wafer alignment control system receives the signal from the photoelectric sensors, processes the data, and outputs instructions according to the preset control algorithm to start wafer detection and control the electromagnetic sliding pin assembly 5 of the wafer alignment mechanism to perform wafer alignment operation.

[0064] As a further improvement to the wafer alignment control method, in step S3, a closed-loop control algorithm can be used to adjust the corresponding PWM duty cycle based on the feedback coil current to synchronously control the magnitude of the electromagnetic force. The specific steps are as follows:

[0065] Step 31: During wafer alignment, determine the movement mode of the electromagnetic sliding pin assembly 5 according to the preset motion trajectory. If the electromagnetic sliding pin assembly 5 is in the acceleration phase, gradually increase the PWM duty cycle according to the preset acceleration parameters to drive the electromagnetic coil 55 to generate a gradually increasing electromagnetic force, thereby accelerating the sliding pin assembly. Or:

[0066] Step S32: If the electromagnetic sliding pin assembly 5 is in the deceleration stage, the PWM duty cycle is gradually reduced according to the preset deceleration parameters, driving the electromagnetic coil to generate a gradually decreasing electromagnetic force, so that the sliding pin assembly decelerates.

[0067] Step S33: Receive the current value of electromagnetic coil 55 in real time, calculate the target PWM duty cycle through closed-loop control algorithm, calculate the deviation between the current coil current value and the target coil current value, and calculate the adjustment amount according to the deviation value and the preset proportional-integral-derivative (PID) control formula.

[0068] Step S34: Apply the adjustment amount to the current PWM duty cycle to generate a new target PWM duty cycle. Based on the new target PWM duty cycle, adjust the output of the PWM signal to control the electromagnetic force of the electromagnetic coil, so that the sliding pin assembly moves along a preset motion trajectory until the center of the wafer is aligned with the center of the wafer placement frustum 6.

[0069] The optimized technical solutions provided in steps S31 to S34 ensure that the electromagnetic sliding pin assembly 5 can accurately reach the designated position by accelerating and then decelerating according to the preset motion trajectory. This is achieved through phased control during the acceleration and deceleration phases, real-time feedback of the electromagnetic coil current value, and calculation of the target PWM duty cycle using a closed-loop control algorithm. The output of the PWM signal is adjusted based on the new target PWM duty cycle, thereby precisely controlling the magnitude of the electromagnetic force and ensuring that the motion trajectory of the electromagnetic sliding pin assembly meets the preset requirements. The closed-loop control algorithm effectively copes with changes in system parameters and external disturbances. Through phased control (acceleration and deceleration phases) and real-time feedback adjustment, it ensures precise motion trajectory movement, avoiding motion errors caused by sudden speed changes or inertia. This allows the wafer alignment control method and system to maintain stable alignment performance under different operating conditions, while also preventing the electromagnetic sliding pin assembly from impacting the wafer due to inertia, thus protecting the wafer from damage and improving wafer yield.

[0070] As an alternative to steps S31 to S34, nonlinear control methods such as sliding mode control algorithms can also be used to achieve precise control of wafer pairing. That is, step S33 can be further improved as follows:

[0071] Step S331, define the sliding surface: set the sliding surface function s(t), where s(y)=e(t)+λ∫e(t)dt, e(t) is the deviation between the current value of the current electromagnetic coil 55 and the target electromagnetic coil current value, and λ is a preset positive number representing the slope of the sliding surface.

[0072] Step S332, calculate the sliding mode control law: calculate the control law u(t) based on the sliding surface function s(t), where u(t) = -k·sign(s(t)), k is the preset control gain, and sign(s(t)) is the sign function, which takes the value of 1 when s(t)>0 and takes the value of -1 when s(t)<0.

[0073] Step S333, Adjust PWM duty cycle: Apply the control law u(t) to the current PWM duty cycle to generate a new target PWM duty cycle.

[0074] In step S332, when the sliding surface function S(t) is greater than zero, it indicates that the system state is above the sliding surface. In this case, the control input needs to be adjusted to reduce the electromagnetic force, causing the wafer alignment control system to move closer to the sliding surface. This involves reducing the duty cycle of the PWM signal, thereby reducing the current in the electromagnetic coil and thus reducing the electromagnetic force. This slows down the movement speed of the electromagnetic sliding pin assembly 5, bringing the wafer alignment control system state closer to the sliding surface. Conversely, when the sliding surface function S(t) is less than zero, it indicates that the wafer alignment control system state is below the sliding surface. In this case, the control input needs to be adjusted to increase the electromagnetic force, causing the wafer alignment control system state to move closer to the sliding surface. This involves increasing the duty cycle of the PWM signal, i.e., increasing the current in the electromagnetic coil 55, increasing the electromagnetic force and thus speeding up the movement speed of the electromagnetic sliding pin assembly 5, bringing the wafer alignment control system state closer to the sliding surface. It can be seen that the position of the system state relative to the sliding surface can be determined by the value of the sliding surface function S(t), and the duty cycle of the PWM signal can be adjusted accordingly. Then, by improving the magnitude of the electromagnetic force, the movement speed of the electromagnetic sliding pin component 5 can be changed, and the system state can be guided to the sliding surface and kept moving on the sliding surface, thereby achieving high-precision control of the wafer alignment unit.

[0075] In summary, the optimized technical solutions provided in steps S31 to S33 ensure that the motion trajectory of the electromagnetic sliding pin assembly 5 strictly conforms to the preset motion trajectory. Utilizing the fast response characteristic of the sliding mode control algorithm, the system output converges rapidly, guiding the system state to the sliding surface and maintaining stability within a short time. This allows the wafer alignment process to be completed quickly, significantly improving production efficiency. Because the sliding mode control algorithm is highly robust to parameter changes and external disturbances, the wafer alignment control system maintains stable alignment performance even under complex operating conditions, ensuring the accuracy and reliability of wafer alignment. Especially during the deceleration phase, by gradually reducing the PWM duty cycle, the electromagnetic force gradually decreases, allowing the sliding pin assembly to decelerate smoothly and stop accurately at the designated position, preventing impact from inertia and protecting the wafer from damage.

[0076] Those skilled in the art will understand that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which the embodiments of this application pertain. It should also be understood that terms such as those defined in general dictionaries should be understood to have a meaning consistent with their meaning in the relevant technical context and should not be interpreted in an idealized or overly formal sense unless specifically defined.

[0077] It should be noted that certain terms are used in the specification and claims of this application to refer to specific elements. Those skilled in the art will understand that different manufacturers or producers may use different terms to refer to the same element. The specification and claims of this application do not distinguish elements based on differences in terminology, but rather on differences in function.

[0078] In the description of the embodiments of this application, the reference to terms such as "an embodiment," "example," "specific example," etc., means that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the embodiments of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0079] Furthermore, the technical solutions of the various implementation methods in this application can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the embodiments of this application.

[0080] All features disclosed in the embodiments of this application, or all steps in the disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps. Any feature disclosed in the specification of the embodiments of this application, unless specifically stated otherwise, may be replaced by other equivalent or similar alternative features. That is, unless specifically stated otherwise, each feature is merely one example of a series of equivalent or similar features. Throughout the specification, the same reference numerals indicate the same elements.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of this application, and are not intended to limit them. Although the embodiments of this application have been described in detail with reference to the foregoing specific implementation methods, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing specific implementation methods, or equivalent substitutions can be made to some or all of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A wafer alignment mechanism, characterized in that, Includes the main unit platform (1), equipment frame (2), and electromagnetic sliding pin assembly (5), wherein: Unit main platform (1), on which a wafer placement frustum (6) is installed, and the unit main platform (1) is provided with a radial groove (11), the radial groove (11) being arranged radially with the wafer placement frustum (6) as the center; An electromagnetic sliding pin assembly (5) has a stop end (521) at one end, which passes through the radial groove (11). The stop end (521) abuts against the outer contour of the wafer. Under electromagnetic drive, the stop end (521) slides along the radial groove (11) toward the center of the wafer placement frustum (6), aligning the center of the wafer with the center of the wafer placement frustum (6). The electromagnetic sliding pin assembly (5) includes: a sliding pin cap (51), a sliding pin (52), a spring (53), a sliding pin housing (54), an electromagnetic coil (55), and a coil end cap (56). The sliding pin (52) is L-shaped, with one end being a stop end (521) and the other end being an abutment end (522). The abutment end (522) abuts against one side of the spring (53), and an electromagnetic coil (55) is provided on the other side of the spring (53). The electromagnetic coil (55) is connected to an external power source and generates electromagnetic force through electromagnetic induction. The sliding pin cap (51) is fastened to the stop end (521) by threads. The abutting end (522) of the sliding pin (52) extends into the pin cavity (542) of the sliding pin housing (54) and abuts against the spring (53). The sliding pin (52) is provided with an easily magnetizable material. The portion of the sliding pin (52) that extends into the pin body cavity (542) is provided with a radially protruding flat key (523). A keyway (541) corresponding to the flat key (523) is provided on the inner wall of the sliding pin housing (54). An electromagnetic coil cavity (543) for accommodating an electromagnetic coil (55) is provided inside the sliding pin housing (54). The electromagnetic coil cavity (543) is connected to the pin body cavity (542). A spring end cap (57) is provided at the opening of the pin body cavity (542). A coil end cap (56) is provided at the opening of the electromagnetic coil cavity (543).

2. The wafer alignment mechanism according to claim 1, characterized in that, The wafer placement platform (6) is located at the center of the unit main platform (1). The stop ends (521) of multiple electromagnetic sliding pin assemblies (5) are arranged to form a shape corresponding to the outer contour of the wafer. A photoelectric sensor (3) is installed on one side of the wafer placement platform (6), and a wire groove (12) is provided on one side of the photoelectric sensor (3).

3. The wafer alignment mechanism according to claim 1, characterized in that, An anti-adsorption groove (61) is provided on the upper surface of the wafer placement frustum (6).

4. The wafer alignment mechanism according to claim 1, characterized in that, The electromagnetic sliding pin assembly (5) is installed on the side of the unit main platform (1) facing away from the wafer placement stage (6). The end of the electromagnetic sliding pin assembly (5) away from the wafer placement stage (6) is the stop end (521), and the stop end (521) is on the same side as the wafer placement stage (6).

5. The wafer alignment mechanism according to claim 1, characterized in that, It also includes a unit leveling assembly (4), which is installed between the unit main platform (1) and the equipment frame (2). The unit leveling assembly (4) includes: fastening bolts (41), spring washers (42), flat washers (43), leveling columns (44), locking nuts (45), and lifting bolts (46), wherein: The lifting bolt (46) passes through the unit main platform (1) and the equipment frame (2). A locking nut (45) is installed between the lifting bolt (46) and the equipment frame (2). A leveling column (44) is provided between the unit main platform (1) and the equipment frame (2). A fastening bolt (41) is provided at the other end of the lifting bolt (46) away from the locking nut (45). A spring washer (42) and a flat washer (43) are installed between the fastening bolt (41) and the unit main platform (1).

6. A wafer processing equipment, characterized in that, The wafer processing equipment is provided with a wafer alignment mechanism as described in any one of claims 1 to 5.

7. A wafer alignment control method for controlling the wafer alignment mechanism according to any one of claims 1 to 5, characterized in that, include: The linear spring force of the spring (53) is determined based on the final displacement of the electromagnetic sliding pin assembly (5). Based on the linear relationship between the linear spring force and the electromagnetic force of the electromagnetic coil (55), the proportional relationship between the PWM duty cycles is determined, and the corresponding PWM signal is generated by the wafer alignment control system. The coil current of the electromagnetic coil (55) is measured in real time, and the measured coil current is fed back to the wafer alignment control system. The corresponding PWM duty cycle is adjusted according to the fed-back coil current to synchronously control the magnitude of the electromagnetic force. During the wafer alignment process, the electromagnetic sliding pin assembly (5) is controlled to accelerate and then decelerate by adjusting the PWM duty cycle. The relationship between the magnitude of the electromagnetic force and the speed of the electromagnetic sliding pin assembly (5) is calculated in real time to align the center of the wafer with the center of the wafer placement frustum (6).

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