Motion table vibration reduction system and scanning electron microscope

Abstract

The invention belongs to the technical field of semiconductor scanning electron microscopes, and particularly discloses a motion platform damping system and a scanning electron microscop.The motion platform damping system comprises a vacuum cavity, a buffer module and a motion control unit, and the buffer module is located on the inner side of the vacuum cavity; a motion table, a scanning electron microscope and a measurement system are further arranged in the vacuum cavity, 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 cavity, a supporting seat is arranged on the side edge of the buffer module, and the supporting seat penetrates through the vacuum cavity and is connected with a foundation. An acceleration sensor and an active shock absorber are installed on the outer side of the vacuum cavity, and the active shock absorber is located between the vacuum cavity and the foundation. The buffer module is used for storing and releasing energy, so that high frequency under impact of driving counterforce of the motion table is converted into low-frequency components, and the buffer module can counteract part of the driving counterforce of the motion table, so that the vibration amplitude is reduced.

Description

Technical Field

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

[0002] The scanning electron microscope uses a focused electron beam to scan and image the sample under test. It has the advantages of large depth of field, high resolution, and a wide range of magnifications. It is used for ultra-high resolution imaging and key image dimension measurement on the surface of semiconductor silicon wafers.

[0003] In a scanning electron microscope, when the motor-driven moving stage is working, the motor-driven reaction force acts on the vacuum chamber and the scanning electron microscope through the moving stage base, thereby generating vibrations, which affect the measuring system of the moving stage and the performance of the electron microscope.

[0004] With the improvement of semiconductor process precision, the resolution requirements of scanning electron microscopes are getting higher and higher, and the precision of the moving stage is becoming more and more stringent. Therefore, the moving stage must be subjected to vibration reduction treatment, otherwise the scanning electron microscope is very susceptible to vibration, which will cause image drift, jitter, deformation or distortion, seriously affecting the imaging and analysis results of the scanning electron microscope. In order to reduce the vibration of the internal and external environment of the electron microscope and obtain higher image quality, the present invention proposes a moving stage vibration reduction system and a scanning electron microscope. Summary of the invention

[0005] The purpose of the present invention is to provide a motion table vibration reduction system and a scanning electron microscope to solve the problems existing in the prior art. The prior art usually uses passive vibration absorbers or active vibration absorbers to reduce the vibration of the internal and external environment of the electron microscope. The first method mainly suppresses vibration by the stiffness and damping of the passive vibration absorber itself, which has the disadvantages of slow response speed, long stabilization time, and inability to suppress low-frequency vibration; the second method introduces modern control algorithms on the basis of passive vibration absorbers, which has fast response speed, short stabilization time, and can suppress low-frequency vibration, etc. However, for occasions with large motion loads, it is often difficult to quickly suppress vibration by active vibration absorbers alone.

[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 moving table, a scanning electron microscope and a measuring system are also provided inside the vacuum chamber, the buffer module is installed on the moving table, the scanning electron microscope and the measuring 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 shock absorber are installed outside the vacuum chamber, and the active shock 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 a low frequency component, 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 on the basis of 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 shock 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 residual low-frequency vibration on the vacuum cavity.

[0010] As a preferred embodiment of the present invention, a bellows is sleeved on the outer side of the support seat between the vacuum chamber 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 seismic source connecting seat is connected to the moving platform, and the seismic source connecting seat, the seismic source adjustment plate, the first vibration isolation layer, the first connecting block, the damper, the second connecting block, the second vibration isolation layer, the support adjustment plate, and the support adapter seat are connected in sequence, wherein the two ends of the damper are connected to the first connecting block and the second connecting block through the damping adapter shaft, the elastic element is installed between the first connecting block and the second connecting 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; along the axial direction of the elastic element, the plurality of dampers are centrally symmetrically distributed about the elastic element; the first vibration isolation layer and the second vibration isolation layer 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 will be introduced into the vacuum cavity, causing the vibration of the vacuum cavity, 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 bottom of the motion platform and the foundation, the first vibration isolation layer in the first connection component of the buffer module and the second vibration isolation layer in the second connection component first isolate and decouple the vibration caused by the driving reaction force of part of the motion platform base; then the compressed elastic element stores and releases energy, converting the high frequency under the impact of the driving reaction force into a low frequency component; and then the energy dissipation characteristics of the damper offset part of the driving reaction force of the motion platform, thereby reducing the vibration amplitude of the vacuum cavity, 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 platform and the real-time motion signal of the motion platform 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 driving control loop for the motion platform, wherein the closed-loop driving control loop 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, position signal and actual acceleration signal, position signal of the motion platform through the driving closed-loop control circuit, and output a control signal to the motion platform driving unit 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 adjust 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 driving closed-loop control strategy of vibration acceleration feedforward based on the control method of the motion control unit through the acceleration sensor, and the vibration acceleration feedforward of the vacuum cavity is added to the driving closed-loop control loop to compensate for the actual acceleration deviation of the motion table 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 corrects the control signal accordingly, and further corrects the driving force to compensate for the actual acceleration signal of the motion platform, thereby reducing the influence of the vibration of the vacuum chamber on the motion platform.

[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 table 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 table into the ground through the motion table buffer module, thereby reducing the vibration caused by the driving force of the motion table from the vibration source. At the same time, a 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 table. 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 diagram of the structure 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 It is a schematic diagram for comparing the 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] In the figure: 1. foundation; 2. active shock absorber; 3. acceleration sensor; 4. vacuum chamber; 5. motion table; 6. scanning electron microscope; 7. measurement system; 8. buffer module; 9. support seat; 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 be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work 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. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying 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, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0034] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] Embodiment 1

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

[0037] A moving table 5, a scanning electron microscope 6 and a measuring system 7 are also provided inside the vacuum chamber 4. A buffer module 8 is installed on the moving 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 penetrates 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 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;

[0039] 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 chamber 4 is measured by the acceleration sensor 3. The active shock 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 table 5 through the vibration acceleration signal of the vacuum chamber 4 fed back by the acceleration sensor 3, so as to compensate and eliminate the residual low-frequency vibration on the vacuum chamber 4.

[0040] Furthermore, a bellows 10 is sleeved on the outer side of the support seat 9 between the vacuum chamber 4 and the foundation 1, and the bellows 10 is provided to improve the sealing effect.

[0041] Embodiment 2

[0042] See also Figure 2 The present invention provides a technical solution: the buffer module 8 includes a source connecting seat 801, a source adjustment plate 802, a first vibration isolation layer 803, a first connecting block 804, a fixing 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 adjustment plate 811, and a support adapter seat 812.

[0043] Furthermore, the source connecting seat 801 is connected to the moving table 5, and the source connecting seat 801, the source adjustment 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 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 connecting block 804 and the second connecting block 809 through the damping adapter shaft 808, the elastic element 807 is installed between the first connecting block 804 and the second connecting block 809 through the fixing seat 805, and the support adapter seat 812 is connected to the support seat 9.

[0044] Furthermore, the source adjustment plate 802 is used to adjust the position of the first vibration isolation layer 803 relative to the 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 vibrate, affecting the motion accuracy and stability of the motion platform 5. After installing the buffer module 8 and the support seat 9 between the bottom of the moving platform 5 and the foundation 1, the first vibration isolation layer 803 in the first connection component of the buffer module 8 and the second vibration isolation layer 810 in the second connection component first isolate and decouple the vibration caused by the driving reaction force of the base of the moving 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 the energy consumption characteristics of the damper 806 offset part of the driving reaction force of the moving platform 5, thereby reducing the vibration amplitude of the vacuum chamber 4, the moving platform 5 and the measurement system 7, and then improving the motion accuracy and stability of the moving platform 5. After many tests, the optimal natural frequency and damping rate parameters of the buffer module 8 are obtained 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 time, the buffer module 8 has the highest efficiency in converting and consuming the driving reaction force.

[0045] Embodiment 3

[0046] See also Figure 3 The present invention provides a technical solution: the motion control unit adjusts and compensates 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:

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

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

[0049] S3. Analyze and compare the motion trajectory planning acceleration signal, position signal and actual acceleration signal, position signal of the motion platform 5 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] Embodiment 4

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

[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, through the acceleration sensor 3, a driving closed-loop control strategy of vibration acceleration feedforward is adopted on the basis of the control method of the motion control unit to operate the motion control unit, and the vibration acceleration feedforward of the vacuum chamber 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:

[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 corrects the control signal accordingly, and further corrects the driving force to compensate for the actual acceleration signal of the moving platform 5 , thereby reducing the influence of the vibration of the vacuum chamber 4 on the moving platform 5 .

[0056] In summary, the present invention further provides an electron microscope, which includes an electron microscope on a motion table vibration reduction system as described in any one of Embodiments 1 to 4.

[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 table buffer module 8, the high-frequency component of the vibration acceleration signal introduced by the driving reaction force acting on the vacuum cavity 4 is effectively converted into low-frequency residual vibration, and the vibration amplitude of the vacuum cavity 4 is greatly reduced; Figure 5 is a comparison diagram of the control error curve of motion stage 5. Figure 5 It can be clearly seen that after adding the motion table buffer module 8, the high-frequency impact of the vacuum chamber 4 is effectively eliminated, the control error can converge quickly, and the motion performance of the motion table 5 is effectively improved, thereby improving the vibration reduction performance and dynamic performance of the whole machine.

[0058] It is worth noting that the entire device is controlled by a main control button. Since the device matched with the control button is a common device and belongs to the existing mature technology, its electrical connection relationship and specific circuit structure will not be described in detail here.

[0059] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A sports table vibration reduction system, characterized in that: It comprises a vacuum chamber (4), a buffer module (8) and a motion control unit, wherein the buffer module (8) is located inside the vacuum chamber (4); A moving table (5), a scanning electron microscope (6) and a measuring system (7) are also arranged inside the vacuum chamber (4); the buffer module (8) is mounted on the moving table (5); the scanning electron microscope (6) and the measuring system (7) are mounted on the side wall of the vacuum chamber (4); a support seat (9) is arranged on the side of the buffer module (8); the support seat (9) penetrates 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); 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) to 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. A sports table vibration reduction system according to claim 1, characterized in that: A bellows (10) is sleeved between the vacuum chamber (4) and the foundation (1) on the outside of the support seat (9), and the bellows (10) is provided to improve the sealing effect.

3. A sports table vibration reduction system according to claim 1, characterized in that: The buffer module (8) comprises a seismic source connection seat (801), a seismic 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); 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; the two ends of the damper (806) are connected to the first connection block (804) and the second connection block (809) via a damping adapter shaft (808); the elastic element (807) is installed between the first connection block (804) and the second connection block (809) via a fixing seat (805); and the support adapter seat (812) is connected to the support seat (9).

4. A sports table vibration reduction system 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); viewed 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 chamber (4), causing the vacuum chamber (4) to vibrate, thereby driving the motion platform (5) and the measurement system (7) to vibrate, thereby improving the motion accuracy and stability of the motion platform (5); after the buffer module (8) and the support seat (9) are installed between the bottom of the motion platform (5) and the foundation (1), the first vibration isolation layer (803) in the first connection component of the buffer module (8) and the second vibration isolation layer (810) in the second connection 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 the energy dissipation characteristics of the damper (806) offset part 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), thereby improving the motion accuracy and stability of the motion platform (5).

5. The sports table vibration reduction system 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 comprises the following steps: S1, providing a driving closed-loop control circuit of 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 the actual position signal of the motion platform (5) in real time; 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 circuit, and output a control signal to the driving unit of the motion platform (5) 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. A sports table vibration reduction system 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 adjust 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 using the acceleration sensor (3) and adopting a driving closed-loop control strategy of vibration acceleration feedforward based on the control method of the motion control unit, wherein the vibration acceleration feedforward of the vacuum chamber (4) is added to the driving closed-loop control loop, and the actual acceleration deviation of the motion platform (5) caused by the driving reaction force vibration is compensated, comprising the following steps: S1, the driving closed-loop control circuit 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 circuit 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 moving platform (5), thereby reducing the influence of the vibration of the vacuum chamber (4) on the moving platform (5).

7. An electron microscope, characterized in that: An electron microscope comprising a motion stage vibration reduction system as described in any one of claims 1-6.

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