A self-tracing two-dimensional displacement measuring device

Abstract

This invention discloses a self-traceable two-dimensional displacement measurement device, relating to the field of precision displacement measurement technology. The device includes: a first radiation source, a second radiation source, a wafer fixing plate, a first silicon wafer, a second silicon wafer, a third silicon wafer, a first radiation detector, a second radiation detector, and an XY two-dimensional displacement platform. It includes displacement measurement modules in the X and Y directions. The first and second silicon wafers are fixed parallel to each other on the wafer fixing plate. The third silicon wafer is parallel to the second silicon wafer, and the distance between the third and second silicon wafers is equal to the distance between the first and second silicon wafers. The third silicon wafer is fixed to the sidewall of the XY two-dimensional displacement platform. The XY two-dimensional displacement platform moves the third silicon wafer along with it, and during the displacement process, the third silicon wafer remains parallel to the second silicon wafer and the distance between them remains constant. This invention can simultaneously achieve two-dimensional displacement measurement with a measurement resolution reaching the sub-nanometer level.

Description

Technical Field

[0001] This invention relates to the field of precision displacement measurement technology, and in particular to a self-traceable two-dimensional displacement measurement device. Background Technology

[0002] With the development of high-end manufacturing, the requirements for nanometer-level high-precision displacement measurement technology are becoming increasingly stringent. Currently, high-precision two-dimensional displacement measurement devices mainly include two-dimensional grating displacement measurement systems. These systems have extremely high requirements for grating fabrication quality, a complex overall structure, and measurement results cannot be directly traced back to the meter definition. Therefore, in some metrological applications, especially those requiring extremely high resolution and accuracy, two-dimensional grating displacement measurement systems are insufficient to meet the measurement needs. Summary of the Invention

[0003] The purpose of this invention is to provide a self-traceable two-dimensional displacement measurement device that can simultaneously perform two-dimensional displacement measurement, achieve sub-nanometer resolution, and allow the measurement results to be directly traced back to the meter definition.

[0004] To achieve the above objectives, the present invention provides the following solution:

[0005] In a first aspect, the present invention provides a self-traceable two-dimensional displacement measuring device, the self-traceable two-dimensional displacement measuring device comprising: a first radiation source, a second radiation source, a wafer fixing plate, a first silicon wafer, a second silicon wafer, a third silicon wafer, a first radiation detector, a second radiation detector, and an XY two-dimensional displacement platform; the crystal planes of the first silicon wafer are a first crystal plane and a second crystal plane that are perpendicular to each other.

[0006] The first radiation source, together with the first silicon wafer, the second silicon wafer, the third silicon wafer, and the first radiation detector, constitutes a displacement measurement module in the X direction.

[0007] The second radiation source, together with the first silicon wafer, the second silicon wafer, the third silicon wafer, and the second radiation detector, constitutes a displacement measurement module in the Y direction.

[0008] The first silicon wafer and the second silicon wafer are fixed parallel to each other on the wafer fixing plate; the third silicon wafer is parallel to the second silicon wafer, and the distance between the third silicon wafer and the second silicon wafer is equal to the distance between the first silicon wafer and the second silicon wafer.

[0009] The third silicon wafer is fixed to the side wall of the XY two-dimensional displacement platform; the XY two-dimensional displacement platform drives the third silicon wafer to move together, and during the displacement process, the third silicon wafer and the second silicon wafer remain parallel and at a constant distance.

[0010] Optionally, the first silicon wafer and the second silicon wafer have completely identical planar dimensions, thickness, and crystal orientation.

[0011] Optionally, the size of the third silicon wafer is larger than the sizes of the first silicon wafer and the second silicon wafer.

[0012] Optionally, the measurement principle of the displacement measurement module in the X direction specifically includes:

[0013] The rays emitted from the first radiation source are incident on the first crystal plane of the first silicon wafer at a Bragg angle and undergo Laue diffraction, splitting into two first diffracted beams. These two first diffracted beams are then incident on the second silicon wafer and undergo Laue diffraction again, generating second diffracted beams. The second diffracted beams converge at the third silicon wafer, producing interference fringes. The third silicon wafer moves along the X-direction following the XY two-dimensional displacement platform. The intensity of the interference signal received by the first radiation detector changes periodically in a sinusoidal manner. For every one-first-crystal-plane spacing distance that the third silicon wafer moves along the X-direction, the interference signal changes for one cycle. Multiplying the number of cycles of the received interference signal by the spacing of the crystal planes participating in diffraction along the X-direction yields the magnitude of the displacement of the third silicon wafer along the X-direction.

[0014] Optionally, the measurement principle of the displacement measurement module in the Y direction specifically includes:

[0015] The rays emitted from the second radiation source are incident on the second crystal plane of the first silicon wafer at a Bragg angle and undergo Laue diffraction, splitting into two third diffracted beams. These two third diffracted beams are then incident on the second silicon wafer and undergo Laue diffraction again, generating a fourth diffracted beam. The fourth diffracted beam converges at the third silicon wafer, producing interference fringes. The third silicon wafer moves along the Y direction following the XY two-dimensional displacement platform. The intensity of the interference signal received by the second radiation detector changes periodically in a sinusoidal manner. For every second crystal plane spacing distance moved by the third silicon wafer along the Y direction, the interference signal changes for one cycle. Multiplying the number of cycles of the received interference signal by the spacing of the crystal planes participating in diffraction along the Y direction yields the magnitude of the displacement of the third silicon wafer along the Y direction.

[0016] Optionally, the target material of the first X-ray source is a Cu target, and the wavelength of the excited X-ray is 0.154 nm.

[0017] Optionally, the target material of the second X-ray source is a Cu target, and the wavelength of the excited X-ray is 0.154 nm.

[0018] Optionally, the target material of the first X-ray source is a molybdenum target, and the wavelength of the excited X-ray is 0.071 nm.

[0019] Optionally, the target material of the second X-ray source is a molybdenum target, and the wavelength of the excited X-ray is 0.071 nm.

[0020] Optionally, the crystal plane of the first silicon wafer is any one of the following: {220} crystal plane and {111} crystal plane / {100} crystal plane and {010} crystal plane / {100} crystal plane and {001} crystal plane / {100} crystal plane and {011} crystal plane.

[0021] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0022] This invention provides a self-traceable two-dimensional displacement measurement device, comprising: a first radiation source, a second radiation source, a wafer fixing plate, a first silicon wafer, a second silicon wafer, a third silicon wafer, a first radiation detector, a second radiation detector, and an XY two-dimensional displacement platform; the first silicon wafer has two mutually perpendicular crystal planes, a first crystal plane and a second crystal plane; the first radiation source, the first silicon wafer, the second silicon wafer, the third silicon wafer, and the first radiation detector constitute a displacement measurement module in the X direction; the second radiation source, the first silicon wafer, the second silicon wafer, the third silicon wafer, and the second radiation detector constitute a displacement measurement module in the Y direction; the first silicon wafer and the second silicon wafer are fixed parallel to each other on the wafer fixing plate; the third silicon wafer is parallel to the second silicon wafer, and the distance between the third silicon wafer and the second silicon wafer is equal to the distance between the first silicon wafer and the second silicon wafer; the third silicon wafer is fixed to the sidewall of the XY two-dimensional displacement platform; the XY two-dimensional displacement platform moves the third silicon wafer together, and during the displacement process, the third silicon wafer and the second silicon wafer remain parallel and the distance remains constant. This invention can simultaneously achieve two-dimensional displacement measurement. Furthermore, because the interplanar spacing itself is at the sub-nanometer level, and the measuring device uses the interplanar spacing as a reference, its measurement resolution can also reach the sub-nanometer level, and the measurement results can be directly traced back to the meter definition. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the overall structure of a self-traceable two-dimensional displacement measuring device according to an embodiment of the present invention.

[0025] Figure 2This is a schematic diagram illustrating the principle of X-direction displacement measurement according to an embodiment of the present invention.

[0026] Figure 3 This is a schematic diagram illustrating the principle of displacement measurement in the Y direction according to an embodiment of the present invention.

[0027] Figure label:

[0028] 101-First radiation source, 102-Second radiation source, 201-Crystal fixing plate, 202-First silicon wafer, 203-Second silicon wafer, 3-Third silicon wafer, 401-First radiation detector, 402-Second radiation detector, 5-XY two-dimensional displacement platform. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] In one exemplary embodiment, such as Figure 1 As shown, a self-traceable two-dimensional displacement measuring device is provided. The self-traceable two-dimensional displacement measuring device includes: a first radiation source 101, a second radiation source 102, a wafer fixing plate 201, a first silicon wafer 202, a second silicon wafer 203, a third silicon wafer 3, a first radiation detector 401, a second radiation detector 402, and an XY two-dimensional displacement platform 5; the crystal planes of the first silicon wafer 202 are a first crystal plane and a second crystal plane that are perpendicular to each other.

[0032] The first radiation source 101, together with the first silicon wafer 202, the second silicon wafer 203, the third silicon wafer 3, and the first radiation detector 401, constitutes a displacement measurement module in the X direction.

[0033] The second radiation source 102, together with the first silicon wafer 202, the second silicon wafer 203, the third silicon wafer 3, and the second radiation detector 402, constitutes a displacement measurement module in the Y direction.

[0034] The first silicon wafer 202 and the second silicon wafer 203 are fixed in parallel on the wafer fixing plate 201; the third silicon wafer 3 is parallel to the second silicon wafer 203 (that is, the three wafers are parallel to each other between the first silicon wafer 202, the second silicon wafer 203 and the third silicon wafer 3), and the distance from the third silicon wafer 3 to the second silicon wafer 203 is equal to the distance from the first silicon wafer 202 to the second silicon wafer 203.

[0035] The third silicon wafer 3 is fixed to the side wall of the XY two-dimensional displacement platform 5; the XY two-dimensional displacement platform 5 drives the third silicon wafer 3 to move together, and during the displacement process, the third silicon wafer 3 and the second silicon wafer 203 remain parallel and at a constant distance.

[0036] As an optional implementation, the first silicon wafer 202 and the second silicon wafer 203 have completely identical planar dimensions, thickness, and crystal orientation.

[0037] As an optional implementation, the size of the third silicon wafer 3 is larger than the sizes of the first silicon wafer 202 and the second silicon wafer 203. The specific size is not limited; it is affected by the measurement range. If a larger measurement range is required, the size of the third silicon wafer 3 can be appropriately increased.

[0038] As an optional implementation, the target material of the first radiation source 101 and the second radiation source 102 is a Cu target, and the wavelength of the excited radiation is 0.154 nm.

[0039] It should be noted that the target materials used for the first X-ray source 101 and the second X-ray source 102 are not limited to Cu targets; they can also be molybdenum targets, with an excitation wavelength of 0.071 nm, or other target materials and excitation wavelengths. The selection of the X-ray source wavelength mainly depends on the absorption of the wavelength of X-rays by the silicon crystal and the intensity of the diffracted light.

[0040] As an optional implementation, the crystal plane of the first silicon wafer 202 is any one of the following: {220} crystal plane and {111} crystal plane / {100} crystal plane and {010} crystal plane / {100} crystal plane and {001} crystal plane / {100} crystal plane and {011} crystal plane.

[0041] It should be noted that, in addition to the listed silicon wafer crystal planes, other mutually perpendicular crystal planes can also be selected to achieve the two-dimensional displacement measurement described in this invention. Since the {220} crystal plane and the {111} crystal plane have high diffraction light intensity, the {220} crystal plane and the {111} crystal plane are selected as the crystal planes of the first silicon wafer 202 in this embodiment.

[0042] like Figure 2As shown, the measurement principle of the displacement measurement module in the X direction specifically includes:

[0043] The rays emitted from the first X-ray source 101 are incident on the first crystal plane of the first silicon wafer 202 at a Bragg angle and undergo Laue diffraction, splitting into two first diffracted beams. The two first diffracted beams are then incident on the second silicon wafer 203 and undergo Laue diffraction again, generating second diffracted beams. The second diffracted beams converge at the third silicon wafer 3 to generate interference fringes. The third silicon wafer 3 moves along the X-direction following the XY two-dimensional displacement platform 5. The intensity of the interference signal received by the first radiation detector 401 changes periodically in a sinusoidal manner. For every distance the third silicon wafer 3 moves along the X-direction equal to the distance between the first crystal planes, the interference signal changes for one cycle. Multiplying the number of cycles of the received interference signal by the distance between the crystal planes participating in diffraction along the X-direction yields the magnitude of the displacement of the third silicon wafer 3 along the X-direction.

[0044] Specifically, the Cu target rays emitted from the first radiation source 101 are incident on the first silicon wafer 202 at a Bragg angle. The wavelength of the Cu target rays is 0.154 nm, and the interplanar spacing of the silicon {220} crystal planes is 0.19202 nm. According to the Bragg equation d... sinθ=nλ (d is the lattice spacing, n is the incident angle, n is the diffraction order, and n is the incident wavelength) calculates the incident angle to be 23.641°. (In this formula, with the wavelength of the X-ray source and the silicon lattice spacing fixed, n is 1. Only when the corresponding calculated incident angle is met can constructive interference occur. Under other incident angles, the intensity of the diffracted light will be affected. The incident angle is only a necessary condition for diffraction to occur. When calculating the displacement, it is only related to the spacing of the 220 crystal planes.) Laue diffraction occurs at the first silicon wafer 202, splitting into two first diffracted beams. These two first diffracted beams are incident on the second silicon wafer 203 and Laue diffraction occurs again, producing second diffracted beams. The second diffracted beams converge at the third silicon wafer 3, producing interference fringes. The third silicon wafer 3 moves along the X direction with the two-dimensional displacement platform 5. The intensity of the interference signal received by the first radiation detector 401 changes periodically in a sinusoidal manner. For every distance of one crystal plane spacing that the third silicon wafer 3 moves along the X direction, the interference signal changes for one cycle. By calculating the number of cycles of the received signal and multiplying it by the spacing of the silicon {220} crystal planes, the magnitude of the displacement of the third silicon wafer 3 along the X direction can be obtained.

[0045] like Figure 3 As shown, the measurement principle of the displacement measurement module in the Y direction specifically includes:

[0046] The rays emitted from the second ray source 102 are incident on the second crystal plane of the first silicon wafer 202 at a Bragg angle and undergo Laue diffraction, splitting into two third diffracted beams. These two third diffracted beams are then incident on the second silicon wafer 203 and undergo Laue diffraction again, generating a fourth diffracted beam. The fourth diffracted beam converges at the third silicon wafer 3, producing interference fringes. The third silicon wafer 3 follows the XY two-dimensional displacement platform 5 and moves along the Y direction. The intensity of the interference signal received by the second radiation detector 402 changes periodically in a sinusoidal manner. For every second crystal plane spacing distance that the third silicon wafer 3 moves along the Y direction, the interference signal changes for one cycle. Multiplying the number of cycles of the received interference signal by the spacing of the crystal planes participating in diffraction along the Y direction yields the magnitude of the displacement of the third silicon wafer 3 along the Y direction.

[0047] Specifically, the Cu target rays emitted by the first radiation source 102 are incident on the first silicon wafer 202 at a Bragg angle. The wavelength of the Cu target rays is 0.154 nm, and the interplanar spacing of the silicon {111} crystal planes is 0.31356 nm. According to the Bragg equation dsinθ=nλ, the incident angle is calculated to be 14.215°. Laue diffraction occurs at the first silicon wafer 202, splitting into two third diffracted beams. These two third diffracted beams are incident on the second silicon wafer 203 and undergo Laue diffraction again, producing a fourth diffracted beam. The fourth diffracted beams converge at the third silicon wafer 3, producing interference fringes. The third silicon wafer 3 moves along the Y direction following the two-dimensional displacement platform 5. The intensity of the interference signal received by the second radiation detector 402 varies periodically with a sinusoidal law. For every distance the third silicon wafer 3 moves along the Y direction by one interplanar spacing, the interference signal changes by one cycle. By calculating the number of cycles of the received signal and multiplying it by the interplanar spacing of the silicon {111} crystal planes, the magnitude of the displacement of the third silicon wafer 3 along the Y direction can be obtained.

[0048] Compared with the prior art, the features and beneficial effects of the present invention are as follows:

[0049] (1) It can simultaneously realize two-dimensional displacement measurement, the measurement resolution can reach the sub-nanometer level, and the measurement results can be directly traced back to the definition of the meter (because the spacing of the 220 crystal plane itself is 0.225nm, which is at the sub-nanometer level, and this measurement method takes the 220 silicon crystal plane spacing as the reference, so its measurement resolution can also reach the sub-nanometer level, and the spacing of other silicon crystal planes is also at the sub-meter level). (The 26th General Conference on Weights and Measures in 2018 proposed to use the silicon {220} crystal plane spacing as the reproduction method of the definition of the meter).

[0050] (2) The space structure is compact. Two sets of X-ray sources and radiation detectors share a set of silicon wafers to realize two-dimensional displacement measurement, which effectively improves the space utilization rate.

[0051] (3) Large measurement range: The third silicon wafer is designed separately from the first and second silicon wafers. The measurement range of the device depends on the motion range of the XY two-dimensional displacement measurement platform, and has a large measurement range.

[0052] The technical features of the above embodiments can be combined in any way. For the sake of brevity, 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.

[0053] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A self-traceable two-dimensional displacement measuring device, characterized in that, The self-traceable two-dimensional displacement measurement device includes: a first radiation source, a second radiation source, a wafer fixing plate, a first silicon wafer, a second silicon wafer, a third silicon wafer, a first radiation detector, a second radiation detector, and an XY two-dimensional displacement platform; the crystal planes of the first silicon wafer are mutually perpendicular first and second crystal planes. The first radiation source, together with the first silicon wafer, the second silicon wafer, the third silicon wafer, and the first radiation detector, constitutes a displacement measurement module in the X direction; The second radiation source, together with the first silicon wafer, the second silicon wafer, the third silicon wafer, and the second radiation detector, constitutes a displacement measurement module in the Y direction; The first silicon wafer and the second silicon wafer are fixed parallel to each other on the wafer fixing plate; the third silicon wafer is parallel to the second silicon wafer, and the distance from the third silicon wafer to the second silicon wafer is equal to the distance from the first silicon wafer to the second silicon wafer; The third silicon wafer is fixed to the side wall of the XY two-dimensional displacement platform; the XY two-dimensional displacement platform drives the third silicon wafer to move together, and during the displacement process, the third silicon wafer and the second silicon wafer remain parallel and at a constant distance.

2. The self-traceable two-dimensional displacement measuring device according to claim 1, characterized in that, The first silicon wafer and the second silicon wafer have completely identical planar dimensions, thickness, and crystal orientation.

3. The self-traceable two-dimensional displacement measuring device according to claim 2, characterized in that, The size of the third silicon wafer is larger than the size of the first silicon wafer and the second silicon wafer.

4. The self-traceable two-dimensional displacement measuring device according to claim 1, characterized in that, The measurement principle of the displacement measurement module in the X direction specifically includes: The rays emitted from the first radiation source are incident on the first crystal plane of the first silicon wafer at a Bragg angle and undergo Laue diffraction, splitting into two first diffracted beams. These two first diffracted beams are then incident on the second silicon wafer and undergo Laue diffraction again, generating second diffracted beams. The second diffracted beams converge at the third silicon wafer, producing interference fringes. The third silicon wafer moves along the X-direction following the XY two-dimensional displacement platform. The intensity of the interference signal received by the first radiation detector changes periodically in a sinusoidal manner. For every one-first-crystal-plane spacing distance that the third silicon wafer moves along the X-direction, the interference signal changes for one cycle. Multiplying the number of cycles of the received interference signal by the spacing of the crystal planes participating in diffraction along the X-direction yields the magnitude of the displacement of the third silicon wafer along the X-direction.

5. The self-traceable two-dimensional displacement measuring device according to claim 1, characterized in that, The measurement principle of the displacement measurement module in the Y direction specifically includes: The rays emitted from the second radiation source are incident on the second crystal plane of the first silicon wafer at a Bragg angle and undergo Laue diffraction, splitting into two third diffracted beams. These two third diffracted beams are then incident on the second silicon wafer and undergo Laue diffraction again, generating a fourth diffracted beam. The fourth diffracted beam converges at the third silicon wafer, producing interference fringes. The third silicon wafer moves along the Y direction following the XY two-dimensional displacement platform. The intensity of the interference signal received by the second radiation detector changes periodically in a sinusoidal manner. For every second crystal plane spacing distance moved by the third silicon wafer along the Y direction, the interference signal changes for one cycle. Multiplying the number of cycles of the received interference signal by the spacing of the crystal planes participating in diffraction along the Y direction yields the magnitude of the displacement of the third silicon wafer along the Y direction.

6. The self-traceable two-dimensional displacement measuring device according to claim 1, characterized in that, The target material of the first X-ray source is a Cu target, and the wavelength of the excited X-ray is 0.154 nm.

7. The self-traceable two-dimensional displacement measuring device according to claim 1, characterized in that, The target material of the second X-ray source is a Cu target, and the wavelength of the excited X-ray is 0.154 nm.

8. The self-traceable two-dimensional displacement measuring device according to claim 1, characterized in that, The target material of the first X-ray source is a molybdenum target, and the wavelength of the excited X-ray is 0.071 nm.

9. The self-traceable two-dimensional displacement measuring device according to claim 1, characterized in that, The target material of the second radiation source is a molybdenum target, and the wavelength of the excited radiation is 0.071 nm.

10. The self-traceable two-dimensional displacement measuring device according to claim 1, characterized in that, The crystal plane of the first silicon wafer is any one of the following: {220} crystal plane and {111} crystal plane / {100} crystal plane and {010} crystal plane / {100} crystal plane and {001} crystal plane / {100} crystal plane and {011} crystal plane.

Images