Multi-degree-of-freedom motion system and operation method thereof

Abstract

The invention relates to a multi-degree-of-freedom motion system and an operation method thereof. The multi-degree-of-freedom motion system comprises a five-degree-of-freedom motion platform and a pre-calibration device. The five-degree-of-freedom motion platform comprises a plurality of motion platforms and hollow structures which are stacked in sequence from bottom to top. The plurality of motion platforms are used to drive a wafer to move in an X direction, a Y direction and a Z direction, and to rotate around the X direction and the Z direction. The hollow structure runs through each motion platform. The size of the hollow structure increases layer by layer from the topmost motion platform to the bottommost motion platform. A detection light beam can pass through the hollow structure from bottom to top and be incident on the wafer. A long arm slit can be arranged in the hollow structure. The long arm slit comprises a motion motor, a light blocking structure and a connection structure arranged between the motion motor and the light blocking structure. The motion motor can drive the light blocking structure to move through the connection structure to adjust the spot size of the detection light beam. The pre-calibration device is used to carry and drive the wafer to rotate around the Y direction.

Description

Technical Field

[0001] The present invention relates to the field of wafer measurement technology, and in particular to a multi-degree-of-freedom motion system and an operation method thereof. Background Art

[0002] X-ray microscopy (XRM), critical dimension small angle X-ray scattering (CD-SAXS) and X-ray computational imaging (XCT) can be used to measure the three-dimensional structure and internal structure of complex chips. The moving axis needs to carry the wafer to perform six-degree-of-freedom movement to achieve the switching of different measurement points and different measurement postures. The X-ray measurement optical path includes an X-ray source, an X-ray monochromatic beam shaping mirror, an X-ray multi-slit (including a long-arm slit close to the wafer), and an X-ray detector. The X-ray beam remains stationary along the X-ray optical path, and the generated X-ray beam passes through the wafer to be measured in a transmission manner, and the detector records the transmitted X-ray signal. When the moving axis carries the wafer to move within the six-degree-of-freedom range, it is necessary to ensure that any structure of the moving axis avoids the X-ray measurement optical path structure, especially the long-arm slit close to the wafer. Therefore, the middle part of each layer of the moving axis is a hollow structure to avoid the X-ray measurement beam. Due to the influence of the angle, the middle hollow structure of each moving axis needs to be reduced layer by layer from the direction away from the wafer to the direction close to the wafer.

[0003] In order to achieve more accurate measurement of the wafer, the motion axis needs to achieve a wider range of wafer rotation angles. However, using the traditional six-degree-of-freedom motion axis to achieve a wider range of wafer rotation angles will bring the following problems:

[0004] 1) Since the six-degree-of-freedom motion axis contains a large number of layers of motion axes, the hollow structure needs to be reduced layer by layer from far away from the wafer to close to the wafer, which makes it easier to interfere with the X-ray beam, limiting the angle measurement range of the wafer, thereby reducing the measurement accuracy;

[0005] 2) Since the six-degree-of-freedom motion axis contains a large number of layers of motion axes, the connection structure between the motion motor of the long-arm slit and the light-blocking structure needs to be designed to be longer, resulting in worse control of the light-blocking structure by the motion motor of the long-arm slit, which in turn leads to worse constraint stability of the X-ray beam and stability of the overall measurement.

[0006] 3) Since the existing six-degree-of-freedom motion axis cannot realize the flipping of the structural and non-structural surfaces of the wafer, when the direction and path of the X-ray optical path are fixed, it is impossible to support the X-ray incident from the top and bottom of the wafer structure, and thus it is impossible to ensure the accuracy of the measurement of the top and bottom structures of the wafer. Summary of the invention

[0007] Based on this, it is necessary to provide a multi-degree-of-freedom motion system and its operation method to achieve a wider range of measurement angles for the wafer, so as to improve the measurement accuracy of the detection beam (such as the beam emitted by CD-SAXS, XRM and XCT equipment) on the wafer, and enable the motion motor at the bottom of the long-arm slit to better control the top light-blocking structure, thereby improving the constraint stability of the detection beam and the stability of the overall machine measurement.

[0008] A multi-degree-of-freedom motion system, comprising:

[0009] A five-degree-of-freedom motion axis, wherein the five-degree-of-freedom motion axis comprises a plurality of motion axes stacked in sequence, the middle of the motion axis is a hollow structure, the wafer to be tested can be carried on the motion axis, the plurality of motion axes are used to drive the wafer to move in the X direction, the Y direction and the Z direction, and to rotate around the X direction and the Z direction, the hollow structure runs through each of the motion axes, and the size of the hollow structure increases and decreases layer by layer from far away from the wafer motion axis to close to the wafer motion axis; when the motion axis rotates, the X-ray measurement beam can pass through the hollow structure and be incident on the wafer; the long arm slit can pass through the In the hollow structure, the long arm slit includes a motion motor, a light blocking structure and a connecting structure arranged between the motion motor and the light blocking structure, the motion motor can drive the light blocking structure to move through the connecting structure to adjust the spot size of the detection light beam; the motion motor is arranged outside the hollow structure and away from the wafer; the light blocking structure is arranged in the hollow structure and close to the wafer, and a pre-calibration device is used for center calibration and direction calibration of the wafer, which can carry and drive the wafer to rotate around the Y direction, wherein the X direction, the Y direction and the Z direction are perpendicular to each other.

[0010] In one embodiment, the five-degree-of-freedom motion axis includes a first motion axis, a second motion axis, a third motion axis and a fourth motion axis which are stacked in sequence from far away from the wafer to close to the wafer. The first motion axis can rotate around the Z direction, the second motion axis can translate along the Z direction, the third motion axis can translate along the X direction, and the fourth motion axis is used to support the wafer and can translate along the Y direction and rotate around the X direction.

[0011] In one embodiment, the fourth motion axis includes four Y-direction translation motors, and the four Y-direction translation motors are divided into two groups, upper and lower, along the Z direction. Each group of Y-direction translation motors includes two Y-direction translation motors. When the four Y-direction translation motors all move in the same direction, the fourth workbench can be translated along the Y direction. When the two upper Y-direction translation motors and the two lower Y-direction translation motors move in opposite directions, the fourth motion axis can rotate around the X direction.

[0012] In one embodiment, each of the movement axes has a first side wall and a second side wall that are oppositely disposed therein, and the first side wall and the second side wall define the hollow structure corresponding to each of the movement axes.

[0013] In one of the embodiments, the five-degree-of-freedom motion axis further includes a fixing component for fixing the wafer, and the fixing component is arranged on the motion axis closest to the wafer.

[0014] In one of the embodiments, the fixing component includes any one of a clamping component and an adsorption component, the clamping component is used to clamp and fix the wafer, and the adsorption component is used to adsorb and fix the wafer.

[0015] In one of the embodiments, a wafer flipping device is further included to flip the wafer measurement surface so as to switch between the pattern surface and the non-pattern surface of the wafer.

[0016] An operating method of the above multi-degree-of-freedom motion system comprises the following steps:

[0017] S1. placing the wafer to be tested on the pre-calibration device, and allowing the pre-calibration device to rotate the wafer around the Y direction to a first set direction;

[0018] S2. Remove the wafer rotated to the first set direction from the pre-calibration device and transfer it to the motion axis of the five-degree-of-freedom motion axis closest to the wafer, so that the five-degree-of-freedom motion axis drives the wafer to move in the X, Y and Z directions, and to rotate around the X and Z directions to achieve measurement of the wafer by the detection beam.

[0019] In one embodiment, it also includes:

[0020] S3. removing the wafer from the motion axis closest to the wafer of the five-degree-of-freedom motion axis and moving it back to the pre-calibration device, and causing the pre-calibration device to rotate the wafer around the Y direction to a second set direction different from the first set direction;

[0021] S4. Remove the wafer rotated to the second set direction from the pre-calibration device and transfer it to the motion axis of the five-degree-of-freedom motion axis closest to the wafer, so that the five-degree-of-freedom motion axis drives the wafer to move in the X direction, the Y direction and the Z direction, and to rotate around the X direction and the Z direction to achieve the measurement of the wafer by the detection beam;

[0022] In one embodiment, step S1 comprises:

[0023] S11. Place the wafer on the pre-calibration device by a robot, and the pre-calibration device identifies the center and direction of the wafer and rotates the wafer around the Y direction to the first set direction.

[0024] The multi-degree-of-freedom motion system provided by the present application rotates the wafer around the Y direction to different required angles through a pre-calibration device, and then transfers the wafer rotated to the set angle to the five-degree-of-freedom motion axis, and uses the five-degree-of-freedom motion axis to drive the wafer to move in the X direction, Y direction and Z direction, and to rotate around the X direction and Z direction. That is, the multi-degree-of-freedom motion system of the present solution realizes the equivalent six-degree-of-freedom motion of the wafer through the cooperation of the five-degree-of-freedom motion axis and the pre-calibration device. Since the multi-degree-of-freedom motion system of the present application removes the traditional six-degree-of-freedom motion axis closest to the wafer and is used to realize the Y direction of the wafer The rotating motion axis reduces the number of layers of the motion axis. Under the condition of maintaining the same structural dimensions and the dimensions of the hollow structure in the middle, the motion axes that drive the wafer to translate along the X, Y and Z directions and rotate around the X and Z directions can be closer to the wafer. The five-degree-of-freedom motion axis in this solution can allow a larger Z-direction rotation angle range, so it is not easy to interfere with the detection beam, thereby achieving a wider range of measurement angles for the wafer, which can be used to improve the measurement accuracy of the detection beam (such as the beam emitted by CD-SAXS, XRM and XCT equipment) on the wafer.

[0025] In addition, since the multi-degree-of-freedom motion system of the present application removes the motion axis of the traditional six-degree-of-freedom motion axis that is closest to the wafer and is used to realize the Y-direction rotation of the wafer, that is, the number of motion axis layers is reduced, the long-arm slit can adopt a shorter connection structure, so that the motion motor at the bottom of the long-arm slit can better control the top light-blocking structure, thereby improving the constraint stability of the detection light beam and the stability of the whole machine measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A diagram showing a combination of a multi-degree-of-freedom motion system and a wafer provided by an embodiment of the present invention;

[0027] Figure 2 A schematic diagram of the state of the five-degree-of-freedom motion axes of the multi-degree-of-freedom motion system in which the detection light beam is vertically incident provided by an embodiment of the present invention;

[0028] Figure 3 A schematic diagram of the states of the five-degree-of-freedom motion axes of the multi-degree-of-freedom motion system for non-vertical incidence of a detection beam provided by an embodiment of the present invention;

[0029] Figure 4 A combined diagram of a pre-calibration device and a wafer for a multi-DOF motion system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0030] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0031] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element at the same time.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0033] like Figure 1 and Figure 2 As shown, the present application provides a multi-degree-of-freedom motion system, which includes a five-degree-of-freedom motion axis 100 and a pre-calibration device 200. The five-degree-of-freedom motion axis 100 includes a plurality of motion axes 110 and a hollow structure 120 stacked in sequence from bottom to top. The wafer 300 to be tested can be carried on the topmost motion axis 110. The plurality of motion axes 110 are used to drive the wafer 300 to move in the X direction, the Y direction and the Z direction, and to rotate around the X direction and the Z direction. The hollow structure 120 runs through each motion axis 110. The size of 120 decreases layer by layer from the direction of the moving axis 110 away from the wafer to the moving axis 110 close to the wafer. The detection beam can pass through the hollow structure 120 from bottom to top and be incident on the wafer 300. 400 can be arranged in the hollow structure 120. The long arm slit 400 includes a motion motor 410, a light blocking structure 420 and a connecting structure 430 arranged between the motion motor 410 and the light blocking structure 420. The motion motor 410 can drive the light blocking structure 420 to move through the connecting structure 430 to adjust the spot size of the detection beam. The pre-calibration device 200 is used to carry and drive the wafer 300 to rotate around the Y direction, wherein the X direction, the Y direction and the Z direction are perpendicular to each other.

[0034] The multi-degree-of-freedom motion system provided by the present application rotates the wafer 300 around the Y direction to different required angles through the pre-calibration device 200, and then transfers the wafer 300 rotated to the set angle to the five-degree-of-freedom motion axis 100, and uses the five-degree-of-freedom motion axis 100 to drive the wafer 300 to move in the X direction, the Y direction and the Z direction, and to rotate around the X direction and the Z direction. That is, the multi-degree-of-freedom motion system of the present solution realizes the equivalent six-degree-of-freedom motion of the wafer 300 through the cooperation of the five-degree-of-freedom motion axis 100 and the pre-calibration device 200. Since the multi-degree-of-freedom motion system of the present application removes the traditional six-degree-of-freedom motion axis closest to the wafer and is used to realize the wafer The motion axis rotating in the Y direction reduces the number of layers of the motion axis. Under the condition of keeping the same structural size and the size of the middle hollow structure 120, the motion axes 110 that drive the wafer 300 to translate along the X direction, the Y direction and the Z direction, and rotate around the X direction and the Z direction can be closer to the wafer 300. The five-degree-of-freedom motion axis 100 in this solution can allow a larger Z-direction rotation angle range, so it is not easy to interfere with the detection light beam, thereby achieving a wider range of measurement angles for the wafer 300, which can be used to improve the measurement accuracy of the detection light beam (such as the light beam emitted by CD-SAXS, XRM and XCT equipment) on the wafer 300.

[0035] In addition, since the multi-degree-of-freedom motion system of the present application removes the motion axis of the traditional six-degree-of-freedom motion axis that is closest to the wafer and is used to realize the rotation of the wafer in the Y direction, that is, the number of motion axis layers is reduced, the long-arm slit 400 can adopt a shorter connecting structure 430, so that the motion motor 410 at the bottom of the long-arm slit 400 can better control the top light-blocking structure 420, thereby improving the constraint stability of the detection light beam and the stability of the whole machine measurement.

[0036] like Figure 2 and Figure 3 As shown, in one embodiment, the five-degree-of-freedom motion axis 100 includes a first motion axis 111, a second motion axis 112, a third motion axis 113 and a fourth motion axis 114 which are stacked in sequence from bottom to top. The first motion axis 111 can rotate around the Z direction, the second motion axis 112 can translate along the Z direction, the third motion axis 113 can translate along the X direction, and the fourth motion axis 114 is used to carry the wafer 300 and can translate along the Y direction and rotate around the X direction. The hollow structure 120 runs through the first motion axis 111, the second motion axis 112, the third motion axis 113 and the fourth motion axis 114.

[0037] The sizes of the fourth movement axis 114, the third movement axis 113, the second movement axis 112, and the first movement axis 111 are increased layer by layer. As described above, in order to ensure that the five-degree-of-freedom movement axis 100 does not cause obstruction in the optical path of the detection light beam, when the detection light beam is non-vertically incident, the size of the middle hollow structure 120 of the fourth movement axis 114, the third movement axis 113, the second movement axis 112, and the first movement axis 111 needs to be increased layer by layer. In one embodiment, the middle hollow structure 120 of the fourth movement axis 114, the third movement axis 113, the second movement axis 112, and the first movement axis 111 are coaxially arranged.

[0038] like Figure 1 As shown, in one embodiment, the fourth motion axis 114 includes four Y-direction translation motors 1142, and the four Y-direction translation motors 1142 are divided into two groups, upper and lower, along the Z direction. Each group of Y-direction translation motors 1142 includes two Y-direction translation motors 1142. When the four Y-direction translation motors 1142 all move in the same direction, the fourth workbench can be translated along the Y direction. When the upper two Y-direction translation motors 1142 and the lower two Y-direction translation motors 1142 move in opposite directions, the fourth motion axis 114 can be rotated around the X direction.

[0039] In one embodiment, each motion axis 110 has a first side wall 101 and a second side wall 102 that are relatively arranged inside, and the first side wall 101 and the second side wall 102 define a hollow structure 120 corresponding to each motion axis 110 , and the motion motor 410 at the bottom of the long arm slit 400 is accommodated in the hollow structure 120 of the first motion axis 111 .

[0040] In one embodiment, the five-degree-of-freedom motion axis 100 further includes a fixing component for fixing the wafer 300, and the fixing component is disposed on the topmost motion axis 110. In one embodiment, the fixing component includes any one of a clamping component and an adsorption component, the clamping component is used to clamp and fix the wafer 300, and the adsorption component is used to adsorb and fix the wafer 300.

[0041] In one embodiment, a wafer flipping device 500 is further added to flip the measurement surface of the wafer 300, so that the pattern surface and the non-pattern surface of the wafer can be switched. The X-ray beam is incident from the top direction and / or the bottom direction of the three-dimensional structure of the wafer, so as to ensure the accuracy of the measurement of the top and bottom structures. The above-mentioned wafer flipping device can be an existing conventional flipping device that can realize the flipping of the wafer, and its specific details will not be repeated here.

[0042] The present application also provides an operating method of the multi-degree-of-freedom motion system, the method comprising the following steps:

[0043] S1. Place the wafer 300 to be tested on the pre-calibration device 200, and let the pre-calibration device 200 rotate the wafer 300 around the Y direction to a first set direction;

[0044] S2. Remove the wafer 300 rotated to the first set direction from the pre-calibration device 200 and transfer it to the top-level motion axis 110 of the five-degree-of-freedom motion axis 100, so that the five-degree-of-freedom motion axis 100 drives the wafer 300 to move in the X direction, the Y direction and the Z direction, and to rotate around the X direction and the Z direction to achieve measurement of the wafer 300 by the detection beam.

[0045] In one embodiment, the method further comprises:

[0046] S3. Remove the wafer 300 from the topmost motion axis 110 of the five-degree-of-freedom motion axis 100 and move it back to the pre-calibration device 200, so that the pre-calibration device 200 rotates the wafer 300 around the Y direction to a second set direction different from the first set direction;

[0047] S4. The wafer 300 rotated to the second set direction is removed from the pre-calibration device 200 and transferred to the topmost motion axis 110 of the five-degree-of-freedom motion axis 100, so that the five-degree-of-freedom motion axis 100 drives the wafer 300 to move in the X direction, the Y direction and the Z direction, and to rotate around the X direction and the Z direction to achieve the measurement of the wafer 300 by the detection beam;

[0048] The above steps can be repeated to perform multiple measurements according to the detection requirements.

[0049] In one embodiment, step S1 includes:

[0050] S11. Place the wafer 300 on the pre-calibration device 200 by a robot, the pre-calibration device 200 identifies the center and direction of the wafer 300, and rotates the wafer 300 to a first set direction around the Y direction. The set direction of rotation on the pre-calibration device is selected according to measurement requirements.

[0051] like Figure 4 As shown, in one embodiment, the wafer 300 has a mark, and the pre-calibration device 200 determines the direction of the wafer 300 by identifying the position of the mark.

[0052] Specifically, the mark may be a notch 310 disposed on the edge of the wafer 300, and the first set direction may be a downward direction of the notch 310 of the wafer 300. Step S11 includes: placing the wafer 300 on the pre-calibration device 200 by a robot, the pre-calibration device 200 identifying the center and direction of the wafer 300, and rotating the wafer 300 around the Y direction to a position where the notch 310 of the wafer 300 is facing downward.

[0053] Optionally, step S3 includes: removing the wafer 300 from the topmost motion axis 110 of the five-degree-of-freedom motion axis 100 by a robot and moving it back to the pre-calibration device 200, so that the pre-calibration device 200 rotates the wafer 300 around the Y direction to a second set direction, for example, a position in which the notch 310 of the wafer 300 faces rightward.

[0054] It should be noted that in steps S2 and S4 , removing the wafer 300 from the pre-calibration device 200 and transferring it to the topmost motion axis 110 of the five-degree-of-freedom motion axis 100 can also be achieved by a robot.

[0055] The wafer 300 is rotated around the Y direction to different required angles by the pre-calibration device 200, and then the wafer 300 rotated to the set angle is transferred to the five-degree-of-freedom motion axis 100, and the five-degree-of-freedom motion axis 100 is used to drive the wafer 300 to move in the X direction, the Y direction and the Z direction, and to rotate around the X direction and the Z direction. That is, the multi-degree-of-freedom motion system of this scheme realizes the equivalent six-degree-of-freedom motion of the wafer 300 through the cooperation of the five-degree-of-freedom motion axis 100 and the pre-calibration device 200. Since the multi-degree-of-freedom motion system of this application removes the traditional six-degree-of-freedom motion axis 110 closest to the wafer 300 and is used to realize the Y-direction rotation of the wafer 300 The moving axis 110 and the reduction in the number of layers of the moving axis 110, while maintaining the same structural size and the size of the middle hollow structure 120, can make the moving axes 110 that drive the wafer 300 to move horizontally along the X direction, the Y direction and the Z direction, and to rotate around the X direction and the Z direction closer to the wafer 300, and the five-degree-of-freedom moving axis 100 in this solution can allow a larger Z-direction rotation angle range, so that it is not easy to interfere with the detection light beam, thereby achieving a wider range of measurement angles for the wafer 300, which can be used to improve the measurement accuracy of the detection light beam (such as the light beam emitted by CD-SAXS, XRM and XCT equipment) on the wafer 300.

[0056] In addition, since the multi-degree-of-freedom motion system of the present application removes the traditional six-degree-of-freedom motion axis 110 that is closest to the wafer 300 and is used to realize the motion axis 110 of the Y direction rotation of the wafer 300, that is, the number of layers of the motion axis 110 is reduced, the long-arm slit 400 can adopt a shorter connecting structure 430, so that the motion motor 410 at the bottom of the long-arm slit 400 can better control the top light-blocking structure 420, thereby improving the constraint stability of the detection light beam and the stability of the whole machine measurement.

[0057] In addition, a transfer mechanism (not shown) may also be included: the transfer mechanism transfers the wafer 300 rotated to a set angle to the wafer flipping device 500, the wafer flipping device 500 is used to carry and drive the wafer 300 to flip to a set wafer structural surface or non-structural surface, the wafer 300 flipped to the set wafer structural surface or non-structural surface is removed from the wafer flipping device 500 and transferred to the top-level motion axis 110 of the five-degree-of-freedom motion axis 100, so that the five-degree-of-freedom motion axis 100 drives the wafer 300 to move horizontally along the X direction, the Y direction and the Z direction, and to rotate around the X direction and the Z direction to realize the measurement of the wafer 300 by the detection beam; the operator can flip the wafer as needed, and there is no sequence requirement for flipping in the operation method of the multi-degree-of-freedom motion system.

[0058] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0059] The above embodiments only express the preferred implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A multi-degree-of-freedom motion system, characterized in that: include: A five-degree-of-freedom motion axis, wherein the five-degree-of-freedom motion axis comprises a plurality of motion axes stacked in sequence, the middle of the motion axis is a hollow structure, the wafer to be tested can be carried on the motion axis, the plurality of motion axes are used to drive the wafer to move in the X direction, the Y direction and the Z direction, and to rotate around the X direction and the Z direction, the hollow structure runs through each of the motion axes, and the size of the hollow structure increases and decreases layer by layer from far away from the wafer motion axis to close to the wafer motion axis; when the motion axis rotates, the X-ray measurement beam can pass through the hollow structure and be incident on the wafer; The long arm slit can be penetrated in the hollow structure, and the long arm slit includes a motion motor, a light blocking structure, and a connecting structure arranged between the motion motor and the light blocking structure, and the motion motor can drive the light blocking structure to move through the connecting structure to adjust the spot size of the detection light beam; The motion motor is arranged outside the hollow structure and away from the wafer; the light blocking structure is arranged in the hollow structure and close to the wafer; The pre-calibration device is used for center calibration and direction calibration of the wafer, and can carry and drive the wafer to rotate around the Y direction, wherein the X direction, the Y direction and the Z direction are perpendicular to each other.

2. The multi-degree-of-freedom motion system according to claim 1, characterized in that: The five-degree-of-freedom motion axis includes a first motion axis, a second motion axis, a third motion axis and a fourth motion axis which are stacked in sequence from far away from the wafer to close to the wafer. The first motion axis can rotate around the Z direction, the second motion axis can translate along the Z direction, the third motion axis can translate along the X direction, and the fourth motion axis is used to carry the wafer and can translate along the Y direction and rotate around the X direction.

3. The multi-degree-of-freedom motion system according to claim 2, characterized in that: The fourth motion axis includes four Y-direction translation motors, and the four Y-direction translation motors are divided into two groups, upper and lower, along the Z direction. Each group of Y-direction translation motors includes two Y-direction translation motors. When the four Y-direction translation motors all move in the same direction, the fourth workbench can be translated along the Y direction. When the two upper Y-direction translation motors and the two lower Y-direction translation motors move in opposite directions, the fourth motion axis can rotate around the X direction.

4. The multi-degree-of-freedom motion system according to claim 1, characterized in that: Each of the movement axes has a first side wall and a second side wall that are oppositely disposed therein, and the first side wall and the second side wall define the hollow structure corresponding to each of the movement axes.

5. The multi-degree-of-freedom motion system according to claim 1, characterized in that: The five-degree-of-freedom motion axis also includes a fixing component for fixing the wafer, and the fixing component is arranged on the motion axis closest to the wafer.

6. The multi-degree-of-freedom motion system according to claim 5, characterized in that: The fixing component includes any one of a clamping component and an adsorption component. The clamping component is used to clamp and fix the wafer, and the adsorption component is used to adsorb and fix the wafer.

7. The multi-degree-of-freedom motion system according to claim 1, characterized in that: It also includes a wafer flipping device for flipping the wafer measurement surface to switch between the pattern surface and the non-pattern surface of the wafer.

8. A method for operating a multi-degree-of-freedom motion system according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. placing the wafer to be tested on the pre-calibration device, and allowing the pre-calibration device to rotate the wafer around the Y direction to a first set direction; S2. Remove the wafer rotated to the first set direction from the pre-calibration device and transfer it to the motion axis of the five-degree-of-freedom motion axis closest to the wafer, so that the five-degree-of-freedom motion axis drives the wafer to move in the X, Y and Z directions, and to rotate around the X and Z directions to achieve measurement of the wafer by the detection beam.

9. The method for operating a multi-degree-of-freedom motion system according to claim 7, characterized in that: Also includes: S3. removing the wafer from the motion axis closest to the wafer of the five-degree-of-freedom motion axis and moving it back to the pre-calibration device, and causing the pre-calibration device to rotate the wafer around the Y direction to a second set direction different from the first set direction; S4. Remove the wafer rotated to the second set direction from the pre-calibration device and transfer it to the motion axis of the five-degree-of-freedom motion axis closest to the wafer, so that the five-degree-of-freedom motion axis drives the wafer to move in the X, Y and Z directions, and to rotate around the X and Z directions to achieve measurement of the wafer by the detection beam.

10. The method for operating a multi-degree-of-freedom motion system according to claim 7, characterized in that: Step S1 includes: S11. Place the wafer on the pre-calibration device by a robot, and the pre-calibration device identifies the center and direction of the wafer and rotates the wafer around the Y direction to the first set direction.

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