A motion stage damping system and scanning electron microscope

Abstract

The application belongs to the technical field of semiconductor scanning electron microscopes, and specifically discloses a motion table damping system and a scanning electron microscope, which comprise a vacuum cavity, a buffer module and a motion control unit, the buffer module is located on the inner side of the vacuum cavity, a motion table, a scanning electron microscope and a measuring system are further arranged in the vacuum cavity, the buffer module is installed on the motion table, the scanning electron microscope and the measuring system are installed on the side wall of the vacuum cavity, a supporting seat is arranged on the side of the buffer module, the supporting seat penetrates through the vacuum cavity and is connected to the foundation, an acceleration sensor and an active damper are installed on the outer side of the vacuum cavity, and the active damper is located between the vacuum cavity and the foundation; the buffer module is used for storing and releasing energy, so as to convert high frequency under the impact of the driving counterforce of the motion table into low frequency components, and the buffer module can offset part of the driving counterforce of the motion table and reduce the vibration amplitude.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor scanning electron microscopes. Background Art

[0002] Scanning electron microscopes use a focused electron beam to scan and image the sample being tested. They have the advantages of large depth of field, high resolution, and a wide range of magnifications. They are used for ultra-high resolution imaging and key dimension measurement of semiconductor silicon wafer surfaces.

[0003] In a scanning electron microscope, when the motor drives the motion stage, the motor-driven reaction force acts on the vacuum chamber and the scanning electron microscope through the motion stage base, thereby generating vibration, which affects the measurement system of the motion stage and the performance of the electron microscope.

[0004] As semiconductor manufacturing processes improve, the resolution requirements for scanning electron microscopes (SEMs) are becoming increasingly higher, placing increasing demands on the accuracy of the motion stage. Therefore, vibration reduction treatment is essential for the motion stage. Otherwise, SEMs are highly susceptible to vibration, which can cause image drift, jitter, deformation, or distortion, seriously affecting SEM imaging and analysis results. To reduce vibrations in the internal and external environments of the SEM and achieve higher image quality, the present invention proposes a motion stage vibration reduction system and a SEM. Summary of the Invention

[0005] The present invention aims to provide a motion stage vibration reduction system and a scanning electron microscope (SEM) to address the problems of the prior art, which typically employs passive or active vibration dampers to reduce vibrations within and outside the microscope. The first method primarily utilizes the stiffness and damping of the passive damper to suppress vibrations, but suffers from shortcomings such as slow response speed, long stabilization time, and inability to suppress low-frequency vibrations. The second method, based on the passive damper, incorporates modern control algorithms, resulting in faster response speed, shorter stabilization time, and the ability to suppress low-frequency vibrations. However, for applications with large motion loads, rapid vibration suppression using active dampers alone is often difficult to achieve.

[0006] The present invention provides a motion table vibration reduction system, comprising a vacuum cavity, a buffer module and a motion control unit, wherein the buffer module is located inside the vacuum cavity.

[0007] A motion table, a scanning electron microscope and a measurement system are also provided inside the vacuum chamber. The buffer module is installed on the motion table. The scanning electron microscope and the measurement system are installed on the side wall of the vacuum chamber. A support seat is provided on the side of the buffer module. The support seat passes through the vacuum chamber and is connected to the foundation. An acceleration sensor and an active vibration absorber are installed on the outside of the vacuum chamber. The active vibration absorber is located between the vacuum chamber and the foundation.

[0008] The buffer module is used to store and release energy, thereby converting the high frequency under the impact of the driving reaction force of the motion platform into low frequency components, and the buffer module can offset part of the driving reaction force of the motion platform and reduce the vibration amplitude.

[0009] A motion control unit is added to the buffer module. The motion control unit is based on a closed-loop control strategy of acceleration feedforward. The vibration signal of the vacuum cavity is measured by the acceleration sensor, and the active vibration absorber performs vibration reduction feedforward control according to the measurement signal of the acceleration sensor. At the same time, the motion control unit can also adjust the driving force output by the motion table drive unit through the vacuum cavity vibration acceleration signal fed back by the acceleration sensor to compensate for and eliminate the low-frequency vibration remaining on the vacuum cavity.

[0010] As a preferred embodiment of the present invention, a bellows is provided on the outer side of the support seat between the vacuum cavity and the foundation, and the bellows is provided to improve the sealing effect.

[0011] As a preferred embodiment of the present invention, the buffer module includes a source connection seat, a source adjustment plate, a first vibration isolation layer, a first connection block, a fixing seat, a damper, an elastic element, a damping adapter shaft, a second connection block, a second vibration isolation layer, a support adjustment plate, and a support adapter seat;

[0012] The source connection seat is connected to the motion platform, and the source connection seat, source adjustment plate, first vibration isolation layer, first connection block, damper, second connection block, second vibration isolation layer, support adjustment plate, and support adapter seat are connected in sequence, wherein the two ends of the damper are connected to the first connection block and the second connection block through the damping adapter shaft, the elastic element is installed between the first connection block and the second connection block through the fixing seat, and the support adapter seat is connected to the support seat.

[0013] As a preferred embodiment of the present invention, the source adjustment plate is used to adjust the position of the first vibration isolation layer relative to the source connection seat, and the support adjustment plate is used to adjust the position of the second vibration isolation layer relative to the support adapter seat. The plurality of dampers are centrally symmetrically distributed about the elastic element, viewed along the axis of the elastic element. The first and second vibration isolation layers are both laminated rubber, and the elastic element is a compression spring. When the motion platform moves, the driving reaction force acting on the bottom of the motion platform is introduced into the vacuum chamber, causing vibration of the vacuum chamber, thereby driving the motion platform and the measurement system to vibrate, affecting the motion accuracy and stability of the motion platform. After the buffer module and the support seat are installed between the motion platform bottom and the foundation, the first vibration isolation layer in the first connection assembly of the buffer module and the second vibration isolation layer in the second connection assembly first isolate and decouple the vibration caused by the driving reaction force of the motion platform base. The compressed elastic element then stores and releases energy, converting the high frequency components of the driving reaction force into low frequency components. The energy dissipation characteristics of the damper then offset part of the driving reaction force of the motion platform, thereby reducing the vibration amplitude of the vacuum chamber, the motion platform, and the measurement system, thereby improving the motion accuracy and stability of the motion platform. After many tests, the optimal natural frequency and damping rate parameters of the motion platform buffer module are obtained as follows: the natural frequency of the motion platform buffer module = the natural frequency of the elastic element / 3, and the damping rate is 0.2. At this time, the motion platform buffer module has the highest efficiency in converting and consuming the driving reaction force.

[0014] As a preferred embodiment of the present invention, the motion control unit adjusts and compensates for the deviation between the motion trajectory planning of the motion stage and the real-time motion signal of the motion stage by driving a closed-loop control loop. The control method of the motion control unit includes the following steps:

[0015] S1. Provide a closed-loop drive control circuit for the motion platform, which collects acceleration signals and position signals of the motion trajectory planning of the motion platform in real time;

[0016] S2, the driving closed-loop control circuit collects the actual acceleration signal and actual position signal of the motion platform in real time;

[0017] S3. Analyze and compare the motion trajectory planning acceleration signal and position signal of the motion platform with the actual acceleration signal and position signal through the drive closed-loop control circuit, and output a control signal to the motion platform drive unit accordingly to adjust the output driving force, thereby compensating for the acceleration deviation and position deviation of the motion platform and improving the motion accuracy and stability of the motion platform.

[0018] As a preferred embodiment of the present invention, the acceleration sensor is used to measure the vibration acceleration signal of the vacuum cavity and feed it back to the motion control unit, so that the motion control unit can regulate the driving force output by the motion stage driving unit according to the vibration acceleration signal of the vacuum cavity;

[0019] The motion control unit is operated by adopting a drive closed-loop control strategy of vibration acceleration feedforward based on the control method of the motion control unit by using the acceleration sensor, and the vibration acceleration feedforward of the vacuum cavity is added to the drive closed-loop control loop to compensate for the actual acceleration deviation of the motion platform caused by the driving reaction force vibration, including the following steps:

[0020] S1, the driving closed-loop control loop collects the vibration acceleration signal of the vacuum cavity in real time through the acceleration sensor, and feeds it forward to the driving closed-loop control loop through the amplifier;

[0021] S2. The driving closed-loop control circuit modifies the control signal accordingly, and further modifies the driving force to compensate for the actual acceleration signal of the motion stage, thereby reducing the influence of the vibration of the vacuum cavity on the motion stage.

[0022] As a preferred embodiment of the present invention, in summary, the present invention further proposes an electron microscope, which includes an electron microscope using any of the motion stage vibration reduction systems described above.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention introduces part of the driving force of the motion platform into the ground through the motion platform buffer module, reducing the vibration caused by the driving force of the motion platform from the vibration source. At the same time, the motion control unit is designed to cooperate with active vibration reduction and feedforward control to achieve effective vibration isolation, so as to quickly suppress the vibration caused by large-load movement and improve the accuracy and stability of the motion platform. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0026] Figure 2 This is a schematic structural diagram of the buffer module of the present invention;

[0027] Figure 3 It is a schematic diagram of the process structure of the present invention;

[0028] Figure 4 Schematic diagram for comparing vibration acceleration curves of the vacuum chamber of the present invention;

[0029] Figure 5 Schematic diagram for comparing control error curves of the motion platform of the present invention.

[0030] Figure: 1, foundation; 2, active vibration damper; 3, acceleration sensor; 4, vacuum chamber; 5, motion table; 6, scanning electron microscope; 7, measurement system; 8, buffer module; 9, support base; 10, bellows;

[0031] 801. Source connection seat; 802. Source adjustment plate; 803. First vibration isolation layer; 804. First connection block; 805. Fixed seat; 806. Damper; 807. Elastic element; 808. Damping adapter shaft; 809. Second connection block; 810. Second vibration isolation layer; 811. Support adjustment plate; 812. Support adapter seat. DETAILED DESCRIPTION

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0033] In the description of the present invention, it should be noted that the terms "vertical", "up", "down", "horizontal", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limiting the present invention.

[0034] In the description of the present invention, it should also be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections or electrical connections; they may refer to direct connections or indirect connections through an intermediate medium; and they may refer to internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0035] Example 1

[0036] See also Figure 1 , the present invention provides a technical solution: a motion table vibration reduction system, comprising a vacuum cavity 4, a buffer module 8 and a motion control unit, wherein the buffer module 8 is located inside the vacuum cavity 4;

[0037] A motion stage 5, a scanning electron microscope 6, and a measurement system 7 are also provided inside the vacuum chamber 4. A buffer module 8 is installed on the motion stage 5. The scanning electron microscope 6 and the measurement system 7 are installed on the side wall of the vacuum chamber 4. A support base 9 is provided on the side of the buffer module 8. The support base 9 passes through the vacuum chamber 4 and is connected to the foundation 1. An acceleration sensor 3 and an active vibration absorber 2 are installed outside the vacuum chamber 4. The active vibration absorber 2 is located between the vacuum chamber 4 and the foundation 1.

[0038] The buffer module 8 is used for storing and releasing energy, so as to convert high frequency into low frequency component under the driving reaction force impact of the moving table 5, and the buffer module 8 can offset part of the driving reaction force of the moving table 5, and reduce the vibration amplitude;

[0039] The motion control unit is added on the basis of the buffer module 8, the motion control unit is based on the closed-loop control strategy of acceleration feedforward, the vibration signal of the vacuum cavity 4 is measured through the acceleration sensor 3, the active damper 2 carries out damping feedforward control according to the measurement signal of the acceleration sensor 3, and the motion control unit can also adjust the driving force output by the driving unit of the moving table 5 through the vibration acceleration signal of the vacuum cavity 4 fed back by the acceleration sensor 3, so as to compensate and offset the residual low-frequency vibration on the vacuum cavity 4.

[0040] Further, the corrugated pipe 10 is sleeved between the vacuum cavity 4 and the foundation 1 outside the support seat 9, and the corrugated pipe 10 is arranged to improve the sealing effect.

[0041] Embodiment two

[0042] Please refer to Figure 2 The application provides a technical scheme: the buffer module 8 comprises a seismic source connecting seat 801, a seismic source adjusting plate 802, a first vibration isolation layer 803, a first connecting block 804, a fixed seat 805, a damper 806, an elastic element 807, a damping adapter shaft 808, a second connecting block 809, a second vibration isolation layer 810, a support adjusting plate 811 and a support adapter seat 812.

[0043] Further, the seismic source connecting seat 801 is connected with the moving table 5, the seismic source connecting seat 801, the seismic source adjusting plate 802, the first vibration isolation layer 803, the first connecting block 804, the damper 806, the second connecting block 809, the second vibration isolation layer 810, the support adjusting plate 811 and the support adapter seat 812 are sequentially connected, wherein the damper 806 is connected with the first connecting block 804 and the second connecting block 809 through the damping adapter shaft 808 at both ends, the elastic element 807 is installed between the first connecting block 804 and the second connecting block 809 through the fixed seat 805, and the support adapter seat 812 is connected with the support seat 9.

[0044] Furthermore, the source adjustment plate 802 is used to adjust the position of the first isolation layer 803 relative to the source connection base 801, and the support adjustment plate 811 is used to adjust the position of the second isolation layer 810 relative to the support adapter 812. Across the axis of the elastic element 807, the multiple dampers 806 are centrally symmetrically distributed about the elastic element 807. Both the first and second isolation layers 803 and 810 are laminated rubber, and the elastic element 807 is a compression spring. When the motion platform 5 moves, the driving reaction force acting on the bottom of the motion platform 5 is introduced into the vacuum chamber 4, causing it to vibrate, which in turn causes the motion platform 5 and the measurement system 7 to vibrate, affecting the motion accuracy and stability of the motion platform 5. After installing the buffer module 8 and support base 9 between the bottom of the motion platform 5 and the foundation 1, the first vibration isolation layer 803 in the first connecting assembly of the buffer module 8 and the second vibration isolation layer 810 in the second connecting assembly first isolate and decouple some of the vibrations caused by the driving reaction force of the base of the motion platform 5. The compressed elastic element 807 then stores and releases energy, converting the high-frequency components under the impact of the driving reaction force into low-frequency components. The energy dissipation characteristics of the damper 806 then offset some of the driving reaction force of the motion platform 5, thereby reducing the vibration amplitude of the vacuum chamber 4, the motion platform 5, and the measurement system 7, and thus improving the motion accuracy and stability of the motion platform 5. After multiple tests, the optimal natural frequency and damping rate parameters of the buffer module 8 were determined as follows: the natural frequency of the buffer module 8 = the natural frequency of the elastic element 807 / 3, and the damping rate is 0.2. At this point, the buffer module 8 has the highest efficiency in converting and consuming the driving reaction force.

[0045] Example 3

[0046] See also Figure 3 The present invention provides a technical solution: a motion control unit adjusts and compensates for the deviation between the motion trajectory planning of the motion stage 5 and the real-time motion signal of the motion stage 5 by driving a closed-loop control loop. The control method of the motion control unit includes the following steps:

[0047] S1, providing a closed-loop control circuit for the motion platform 5, which collects acceleration signals and position signals of the motion trajectory planning of the motion platform 5 in real time;

[0048] S2, driving the closed-loop control circuit to collect the actual acceleration signal and actual position signal of the motion stage 5 in real time;

[0049] S3. Analyze and compare the motion trajectory planning acceleration signal and position signal of the motion platform 5 with the actual acceleration signal and position signal through the driving closed-loop control loop, and output a control signal to the driving unit of the motion platform 5 accordingly to adjust the output driving force, thereby compensating for the acceleration deviation and position deviation of the motion platform 5 and improving the motion accuracy and stability of the motion platform 5.

[0050] Example 4

[0051] See also Figure 3 The present invention provides a technical solution: Due to the action of the driving reaction force, the vacuum chamber 4 and the motion platform 5 vibrate, which causes a lot of vibration interference to the actual acceleration signal and actual position signal of the motion platform 5, affecting the accuracy of the feedback actual acceleration signal and actual position signal. In particular, the feedback acceleration signal has relatively high precision requirements. If the actual acceleration signal fed back is inaccurate, the acceleration deviation of the motion platform 5 obtained by subsequent control will be large. Therefore, in order to further improve the motion accuracy and stability of the motion platform 5, it is necessary to compensate the vibration acceleration signal of the vacuum chamber 4 for the feedback actual acceleration signal.

[0052] The acceleration sensor 3 is used to measure the vibration acceleration signal of the vacuum chamber 4 and feed it back to the motion control unit so that the motion control unit can adjust the driving force output by the driving unit of the motion platform 5 according to the vibration acceleration signal of the vacuum chamber 4 .

[0053] Furthermore, the motion control unit is operated by adopting a drive closed-loop control strategy of vibration acceleration feedforward based on the control method of the motion control unit through the acceleration sensor 3. The vibration acceleration feedforward of the vacuum chamber 4 is added to the drive closed-loop control loop to compensate for the actual acceleration deviation of the motion platform 5 caused by the driving reaction force vibration, including the following steps:

[0054] S1, the driving closed-loop control loop collects the vibration acceleration signal of the vacuum cavity 4 in real time through the acceleration sensor 3, and feeds it forward to the driving closed-loop control loop through the amplifier;

[0055] S2 , the driving closed-loop control circuit modifies the control signal accordingly, and further modifies the driving force to compensate for the actual acceleration signal of the motion stage 5 , thereby reducing the influence of the vibration of the vacuum chamber 4 on the motion stage 5 .

[0056] In summary, the present invention further provides an electron microscope, which includes an electron microscope on which the motion stage vibration reduction system described in any one of embodiments one to four is applied.

[0057] The motion platform buffer module 8 of the present invention is simulated by Matlab's simulink, and the simulation performance of the motion platform buffer module 8 is obtained as follows: Figure 4 and 5 As shown, Figure 4 The vibration acceleration curve comparison diagram of the vacuum chamber 4 is shown in FIG. Figure 4 It can be seen that after adding the motion platform buffer module 8, the high-frequency components of the vibration acceleration signal introduced by the driving reaction force acting on the vacuum cavity 4 are effectively converted into low-frequency residual vibrations, and the vibration amplitude of the vacuum cavity 4 is greatly reduced; Figure 5 The control error curve comparison diagram of motion stage 5 is shown in Figure 2.Figure 5 As can be clearly seen, the high-frequency impact of the vacuum cavity 4 is effectively eliminated after the motion table buffer module 8 is added, the control error can quickly converge, the motion performance of the motion table 5 is effectively improved, and thus the vibration reduction performance and dynamic performance of the whole machine are improved.

[0058] It is worth noting that the whole device is controlled by a total control button, and since the control button is matched with common devices, it belongs to existing mature technology, and the electrical connection relationship and specific circuit structure are not described herein.

[0059] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, replacements and changes can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A motion platform vibration reduction system, characterized in that: It comprises a vacuum cavity (4), a buffer module (8) and a motion control unit, wherein the buffer module (8) is located inside the vacuum cavity (4); A motion table (5), a scanning electron microscope (6) and a measuring system (7) are further provided inside the vacuum chamber (4); the buffer module (8) is installed on the motion table (5); the scanning electron microscope (6) and the measuring system (7) are installed on the side wall of the vacuum chamber (4); a support seat (9) is provided on the side of the buffer module (8); the support seat (9) passes through the vacuum chamber (4) and is connected to the foundation (1); an acceleration sensor (3) and an active vibration damper (2) are installed outside the vacuum chamber (4); the active vibration damper (2) is located between the vacuum chamber (4) and the foundation (1); The buffer module (8) is used to store and release energy, thereby converting the high frequency under the impact of the driving reaction force of the motion platform (5) into a low frequency component, and the buffer module (8) can offset part of the driving reaction force of the motion platform (5) and reduce the vibration amplitude; A motion control unit is added on the basis of the buffer module (8). The motion control unit is based on a closed-loop control strategy of acceleration feedforward. The vibration signal of the vacuum cavity (4) is measured by the acceleration sensor (3). The active vibration absorber (2) performs vibration reduction feedforward control according to the measurement signal of the acceleration sensor (3). At the same time, the motion control unit can also adjust the driving force output by the driving unit of the motion platform (5) through the vibration acceleration signal of the vacuum cavity (4) fed back by the acceleration sensor (3) to compensate for and eliminate the low-frequency vibration remaining on the vacuum cavity (4).

2. The vibration reduction system for a sports table according to claim 1, characterized in that: A bellows (10) is sleeved on the outside of the support seat (9) between the vacuum cavity (4) and the foundation (1), and the bellows (10) is provided to improve the sealing effect.

3. The vibration reduction system for a sports table according to claim 1, characterized in that: The buffer module (8) comprises a vibration source connection seat (801), a vibration source adjustment plate (802), a first vibration isolation layer (803), a first connection block (804), a fixing seat (805), a damper (806), an elastic element (807), a damping adapter shaft (808), a second connection block (809), a second vibration isolation layer (810), a support adjustment plate (811), and a support adapter seat (812); The seismic source connection seat (801) is connected to the motion platform (5), and the seismic source connection seat (801), the seismic source adjustment plate (802), the first vibration isolation layer (803), the first connection block (804), the damper (806), the second connection block (809), the second vibration isolation layer (810), the support adjustment plate (811), and the support adapter seat (812) are connected in sequence, wherein the two ends of the damper (806) are connected to the first connection block (804) and the second connection block (809) through the damping adapter shaft (808), the elastic element (807) is installed between the first connection block (804) and the second connection block (809) through the fixing seat (805), and the support adapter seat (812) is connected to the support seat (9).

4. The vibration reduction system for a sports table according to claim 3, characterized in that: The vibration source adjustment plate (802) is used to adjust the position of the first vibration isolation layer (803) relative to the vibration source connection seat (801), and the support adjustment plate (811) is used to adjust the position of the second vibration isolation layer (810) relative to the support adapter seat (812); along the axial direction of the elastic element (807), the plurality of dampers (806) are centrally symmetrically distributed about the elastic element (807); the first vibration isolation layer (803) and the second vibration isolation layer (810) are both laminated rubber, and the elastic element (807) is a compression spring. When the motion platform (5) moves, the driving reaction force acting on the bottom of the motion platform (5) will be introduced into the vacuum cavity (4), causing the vacuum cavity (4) to vibrate, thereby driving the motion platform (5) and the measurement system (7) to follow The invention relates to a method for improving the motion accuracy and stability of the motion platform (5) by means of vibration; after installing a buffer module (8) and a support seat (9) between the bottom of the motion platform (5) and the foundation (1), the first vibration isolation layer (803) in the first connecting component of the buffer module (8) and the second vibration isolation layer (810) in the second connecting component first isolate and decouple the vibration caused by the driving reaction force of the base of the motion platform (5); then the compressed elastic element (807) stores and releases energy, converting the high frequency under the impact of the driving reaction force into a low frequency component; and then offsetting the driving reaction force of the motion platform (5) by means of the energy dissipation characteristics of the damper (806), thereby reducing the vibration amplitude of the vacuum chamber (4), the motion platform (5) and the measurement system (7), thereby improving the motion accuracy and stability of the motion platform (5).

5. The vibration reduction system for a sports table according to claim 1, characterized in that: The motion control unit adjusts and compensates for the deviation between the motion trajectory planning of the motion platform (5) and the real-time motion signal of the motion platform (5) by driving a closed-loop control loop. The control method of the motion control unit includes the following steps: S1, providing a driving closed-loop control circuit for the motion platform (5), wherein the driving closed-loop control circuit collects acceleration signals and position signals of the motion trajectory planning of the motion platform (5) in real time; S2, the driving closed-loop control circuit collects the actual acceleration signal and actual position signal of the motion platform (5) in real time; S3, analyzing and comparing the motion trajectory planning acceleration signal and position signal of the motion platform (5) with the actual acceleration signal and position signal through the driving closed-loop control circuit, and outputting a control signal to the motion platform (5) driving unit accordingly to adjust the output driving force, thereby compensating for the acceleration deviation and position deviation of the motion platform (5), and improving the motion accuracy and stability of the motion platform (5).

6. The vibration reduction system for a sports table according to claim 1, characterized in that: The acceleration sensor (3) is used to measure the vibration acceleration signal of the vacuum cavity (4) and feed it back to the motion control unit, so that the motion control unit can regulate the driving force output by the driving unit of the motion platform (5) according to the vibration acceleration signal of the vacuum cavity (4); The motion control unit is operated by adopting a driving closed-loop control strategy of vibration acceleration feedforward based on the control method of the motion control unit through the acceleration sensor (3), and the vibration acceleration feedforward of the vacuum cavity (4) is added to the driving closed-loop control loop to compensate for the actual acceleration deviation of the motion table (5) caused by the driving reaction force vibration, including the following steps: S1, the driving closed-loop control loop collects the vibration acceleration signal of the vacuum cavity (4) in real time through the acceleration sensor (3), and feeds it forward to the driving closed-loop control loop through the amplifier; S2, the driving closed-loop control circuit corrects the control signal accordingly, and further corrects the driving force to compensate for the actual acceleration signal of the motion platform (5), thereby reducing the influence of the vibration of the vacuum cavity (4) on the motion platform (5).

7. An electron microscope, characterized in that: The invention comprises an electron microscope using the motion stage vibration reduction system as described in any one of claims 1 to 6.

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