X-ray interferometer for picometer-level translation stage and displacement measurement method

Abstract

The present application discloses an X-ray interferometer and a displacement measurement method for a picometer-level displacement stage, and relates to the field of interferometers. In the interferometer, a first beam splitter is arranged on an outgoing light path of an X-ray source; a first reflector and a second beam splitter are arranged on a transmitted light path of the first beam splitter, respectively; an analyzer is arranged on a reflected light path of the first reflector and a first transmitted light path of the second beam splitter; a third beam splitter is arranged on a second transmitted light path of the second beam splitter; a second reflector is arranged on a reflected light path of the third beam splitter; a third reflector is arranged on a transmitted light path of the third beam splitter; a third beam splitter is arranged on reflected light paths of the second and third reflectors; a detection module is arranged on the outgoing light paths of the analyzer and the third beam splitter to detect the intensity of interference fringes, and a processor calculates displacements in X and Y directions according to the intensity. The present application can realize simultaneous picometer-level precision measurement of two-dimensional motion with only one light source, and has a simple structure and low radiation risk.

Description

Technical Field

[0001] The present application relates to the field of interferometers, and in particular to an X-ray interferometer for a picometer-level displacement stage and a displacement measurement method. Background Art

[0002] Laser interferometers are used for displacement measurement and are widely used in precision machinery, semiconductor manufacturing and other fields. Although optical interferometers are widely used in the field of measurement, their nonlinear characteristics are a significant disadvantage. Therefore, one of the focuses of laser interferometer research is how to evaluate and reduce the impact of nonlinear effects on measurement results. The measurement uncertainty of new optical interferometer equipment currently reaches tens of picometers. X-ray interferometers are known for their atomic-level resolution, which has unique advantages over other nanometer-resolution sensors such as optical interferometers and atomic force microscopes. The wavelength of X-rays is at the sub-nanometer level, and the zone-melted single-crystal silicon used to make interferometers has a very regular and stable atomic arrangement, which makes it an ideal picometer-level length unit.

[0003] The current X-ray interferometers are composed of a single X-ray source, a set of chips (from left to right: beam splitter, reflector and analyzer), and a radiation detector, and can only measure one-dimensional motion. There is currently no X-ray interferometer that can measure the displacement of the XY two-dimensional degree of freedom. If you want to measure two-dimensional motion at the same time, such as measuring the two-dimensional movement of the probe relative to the sample under test in a scanning probe microscope, the conventional practice is to build two interferometers to measure the displacement in the X and Y directions respectively. For X-ray interferometers, two light sources are required, the structure is very complex and large, and the radiation risk of the rays is relatively high. The installation of the two interferometers and the adjustment of the ray angles are also relatively difficult. Therefore, there is an urgent need for an interferometer with a simple structure that can simultaneously measure two-dimensional motion with picometer-level accuracy using only one X-ray source. Summary of the invention

[0004] The purpose of this application is to provide an X-ray interferometer and displacement measurement method for a picometer-level translation stage, which has a simple structure and can simultaneously measure two-dimensional motion with picometer-level accuracy using only one X-ray source. It has a simple structure and low radiation risk.

[0005] To achieve the above objectives, this application provides the following solutions.

[0006] In the first aspect, the present application provides an X-ray interferometer for a picometer-level translation stage, comprising: an X-ray source, a first beam splitter, a second beam splitter, a third beam splitter, a first reflector, a second reflector, a third reflector, an analyzer, a detection module and a processor; the third reflector and the analyzer are arranged on the moving part of the picometer-level translation stage; the first beam splitter, the second beam splitter, the third beam splitter, the first reflector, the second reflector, the third reflector and the analyzer are all crystals.

[0007] The first beam splitter is arranged on the outgoing light path of the X-ray source; the first reflector is arranged on the reflected light path of the first beam splitter; the second beam splitter is arranged on the transmitted light path of the first beam splitter; the reflected light path of the first beam splitter and the transmitted light path of the first beam splitter are perpendicular to each other; and the analyzer is arranged on the reflected light path of the first reflector and the reflected light path of the second beam splitter.

[0008] The third beam splitter is arranged on the transmission light path of the second beam splitter; the second reflector is arranged on the reflection light path of the third beam splitter; the third reflector is arranged on the transmission light path of the third beam splitter; the third beam splitter is arranged on the reflection light path of the second reflector and the reflection light path of the third reflector.

[0009] The detection module is arranged on the output light path of the analyzer and the output light path of the third spectrometer, and the detection module is used to detect the intensity of the interference fringes generated by the output light path of the analyzer and the intensity of the interference fringes generated by the output light path of the third spectrometer; the processor is connected to the detection module, and the processor is used to calculate the displacement of the picometer-level displacement stage in the X direction and the Y direction according to the intensity of the interference fringes generated by the output light path of the analyzer and the intensity of the interference fringes generated by the output light path of the third spectrometer; the X direction is perpendicular to the Y direction.

[0010] Optionally, the X-ray interferometer for the picometer-level translation stage further includes: a first phase adjuster; the first phase adjuster is arranged on the reflected light path of the first beam splitter; and the first reflector is arranged on the output light path of the first phase adjuster.

[0011] Optionally, the detection module includes: a first detection unit and a second detection unit; the first detection unit is arranged on the output light path of the analyzer, and the first detection unit is used to detect the intensity of the interference fringes generated by the output light path of the analyzer; the second detection unit is arranged on the output light path of the third spectrometer, and the second detection unit is used to detect the intensity of the interference fringes generated by the output light path of the third spectrometer.

[0012] Optionally, the first detection unit includes: a first detector and a second detector; the first detector is arranged on a first outgoing light path of the analyzer, and the second detector is arranged on a second outgoing light path of the analyzer.

[0013] Optionally, the interference fringes generated by the first outgoing light path of the analyzer and the interference fringes generated by the second outgoing light path of the analyzer differ in phase by 90 degrees.

[0014] Optionally, the second detection unit includes: a third detector and a fourth detector; the third detector is arranged on a first outgoing light path of the third spectrometer, and the fourth detector is arranged on a second outgoing light path of the third spectrometer.

[0015] Optionally, the interference fringes generated by the first outgoing light path of the third beam splitter and the interference fringes generated by the second outgoing light path of the third beam splitter have a phase difference of 90 degrees.

[0016] In a second aspect, the present application provides a displacement measurement method for a picometer-level translation stage, which is applied to the X-ray interferometer for the picometer-level translation stage described in any of the above items, and the displacement measurement method for the picometer-level translation stage includes: obtaining the intensity of the interference fringes generated by the output light path of the analyzer after the moving part of the picometer-level translation stage moves and the intensity of the interference fringes generated by the output light path of the third spectrometer.

[0017] The displacement of the picometer stage in the X direction is obtained according to the intensity of the interference fringes generated in the outgoing light path of the analyzer after the moving part of the picometer stage moves.

[0018] The displacement of the picometer-level translation stage in the Y direction is obtained according to the intensity of the interference fringes generated by the outgoing light path of the third beam splitter after the moving part of the picometer-level translation stage moves.

[0019] Optionally, the displacement of the picometer-level displacement stage in the X direction is obtained according to the intensity of the interference fringes generated in the output light path of the analyzer after the moving part of the picometer-level displacement stage moves, specifically including: calculating the period of the interference fringes generated in the output light path of the analyzer after the moving part of the picometer-level displacement stage moves according to the intensity of the interference fringes generated in the output light path of the analyzer after the moving part of the picometer-level displacement stage moves.

[0020] The displacement of the picometer stage in the X direction is obtained by calculating the product of the period of the interference fringes generated by the outgoing light path of the analyzer after the moving part of the picometer stage moves and the lattice spacing of the analyzer.

[0021] Optionally, the displacement of the picometer-level translation stage in the Y direction is obtained according to the intensity of the interference fringes generated by the output light path of the third beam splitter after the moving part of the picometer-level translation stage moves, specifically including: calculating the period of the interference fringes generated by the output light path of the third beam splitter after the moving part of the picometer-level translation stage moves according to the intensity of the interference fringes generated by the output light path of the third beam splitter after the moving part of the picometer-level translation stage moves.

[0022] The displacement of the picometer stage in the Y direction is obtained by calculating the product of the period of the interference fringes generated by the output light path of the third beam splitter after the moving part of the picometer stage moves and the lattice spacing of the third beam splitter.

[0023] According to the specific embodiments provided by the present application, the present application has the following technical effects: the present application provides an X-ray interferometer and a displacement measurement method for a picometer-level displacement stage, wherein the interferometer uses a first beam splitter to split a beam of light emitted by an X-ray source into two beams along mutually perpendicular directions, and respectively forms an interferometer perpendicular to two directions with a second beam splitter, a third beam splitter, a first reflector, a second reflector, a third reflector and an analyzer, and only one X-ray source can be used to achieve simultaneous displacement measurement in the X and Y dimensions, and the structure is simple. Compared with using two X-ray sources, using only one X-ray source has a small radiation risk, and by using short-wavelength X-rays, the period of the interference fringes generated can be reduced to 200 picometers, so the picometer-level displacement can be directly obtained through the interference fringes, and the measurement of picometer-level accuracy can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 A schematic diagram of the structure of an X-ray interferometer for a picometer-level translation stage provided in one embodiment of the present application.

[0026] Figure 2 The working principle diagram of the analyzer is shown in Figure 2.

[0027] Figure 3 This is the working principle diagram of the third splitter. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0029] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0030] In an exemplary embodiment, an X-ray interferometer for a picometer-level translation stage is provided, such as Figure 1 As shown, the X-ray interferometer for the picometer stage comprises: an X-ray source 1, a first beam splitter 2, a second beam splitter 3, a third beam splitter 4, a first reflector 5, a second reflector 6, a third reflector 7, an analyzer 8, a detection module and a processor; the third reflector 7 and the analyzer 8 are arranged on the moving part of the picometer stage 14. The first beam splitter 2, the second beam splitter 3, the third beam splitter 4, the first reflector 5, the second reflector 6, the third reflector 7 and the analyzer 8 are all crystals, which can be single crystal silicon crystals.

[0031] The first beam splitter 2 is arranged on the outgoing light path of the X-ray source 1; the first reflector 5 is arranged on the reflected light path of the first beam splitter 2; the second beam splitter 3 is arranged on the transmitted light path of the first beam splitter 2; the reflected light path of the first beam splitter 2 and the transmitted light path of the first beam splitter 2 are perpendicular to each other; the analyzer 8 is arranged on the reflected light path of the first reflector 5 and the reflected light path of the second beam splitter 3.

[0032] The third beam splitter 4 is arranged on the transmitted light path of the second beam splitter 3; the second reflector 6 is arranged on the reflected light path of the third beam splitter 4; the third reflector 7 is arranged on the transmitted light path of the third beam splitter 4; the third beam splitter 4 is arranged on the reflected light path of the second reflector 6 and the reflected light path of the third reflector 7.

[0033] The detection module is arranged on the output light path of the analyzer 8 and the output light path of the third spectrometer 4, and the detection module is used to detect the intensity of the interference fringes generated by the output light path of the analyzer 8 and the intensity of the interference fringes generated by the output light path of the third spectrometer 4; the processor is connected to the detection module, and the processor is used to calculate the displacement of the picometer-level displacement stage 14 in the X direction and the Y direction according to the intensity of the interference fringes generated by the output light path of the analyzer 8 and the intensity of the interference fringes generated by the output light path of the third spectrometer 4; the X direction is perpendicular to the Y direction.

[0034] In another exemplary embodiment of the present application, the X-ray interferometer for the picometer-level translation stage further includes: a first phase adjuster 9; the first phase adjuster 9 is arranged on the reflected light path of the first beam splitter 2; and the first reflector 5 is arranged on the output light path of the first phase adjuster 9.

[0035] In another exemplary embodiment of the present application, the X-ray interferometer for the picometer-level translation stage further includes: a second phase adjuster 15 ; the second phase adjuster 15 is arranged on the reflected light path of the third beam splitter 4 ; and the second reflector 6 is arranged on the output light path of the second phase adjuster 15 .

[0036] In another exemplary embodiment of the present application, the detection module includes: a first detection unit and a second detection unit; the first detection unit is arranged on the output light path of the analyzer 8, and the first detection unit is used to detect the intensity of the interference fringes generated by the output light path of the analyzer 8; the second detection unit is arranged on the output light path of the third spectrometer 4, and the second detection unit is used to detect the intensity of the interference fringes generated by the output light path of the third spectrometer 4.

[0037] In another exemplary embodiment of the present application, the first detection unit includes: a first detector 10 and a second detector 12; the first detector 10 is arranged on the first outgoing light path of the analyzer 8, and the second detector 12 is arranged on the second outgoing light path of the analyzer 8. The first detector 10 is used to detect the intensity of the interference fringes generated by the first outgoing light path of the analyzer 8, and the second detector 12 is used to detect the intensity of the interference fringes generated by the second outgoing light path of the analyzer 8, and the processor is used to obtain the phase angle of the interference fringes generated by the outgoing light path of the analyzer 8 according to the intensity of the interference fringes generated by the first outgoing light path of the analyzer 8 and the intensity of the interference fringes generated by the second outgoing light path of the analyzer 8.

[0038] In another exemplary embodiment of the present application, the optical path difference between the rays reaching the first detector 10 and the rays reaching the second detector 12 is adjusted by the first phase adjuster 9, so that the phases of the interference fringes generated by the first outgoing light path of the analyzer 8 and the interference fringes generated by the second outgoing light path of the analyzer 8 differ by 90 degrees.

[0039] In another exemplary embodiment of the present application, the wavelength of the X-ray emitted by the X-ray source 1 satisfies the Bragg diffraction condition of the crystal. The X-ray source 1 is an X-ray source with adjustable wavelength.

[0040] In another exemplary embodiment of the present application, the second detection unit includes: a third detector 11 and a fourth detector 13; the third detector 11 is arranged on the first outgoing light path of the third beam splitter 4, and the fourth detector 13 is arranged on the second outgoing light path of the third beam splitter 4. The third detector 11 is used to detect the intensity of the interference fringes generated by the first outgoing light path of the third beam splitter 4, and the fourth detector 13 is used to detect the intensity of the interference fringes generated by the second outgoing light path of the third beam splitter 4. The processor is used to obtain the phase angle of the interference fringes generated by the outgoing light path of the third beam splitter 4 according to the intensity of the interference fringes generated by the first outgoing light path of the third beam splitter 4 and the intensity of the interference fringes generated by the second outgoing light path of the third beam splitter 4.

[0041] The processor obtains the period of the interference fringes generated by the output light path of the analyzer 8 according to the phase angle of the interference fringes generated by the output light path of the analyzer 8; the processor obtains the period of the interference fringes generated by the output light path of the third spectrometer 4 according to the phase angle of the interference fringes generated by the output light path of the third spectrometer 4.

[0042] In another exemplary embodiment of the present application, the optical path difference between the rays reaching the third detector 11 and the rays reaching the fourth detector 13 is adjusted by the second phase adjuster 15, so that the phases of the interference fringes generated by the first outgoing light path of the third beam splitter 4 and the interference fringes generated by the second outgoing light path of the third beam splitter 4 differ by 90 degrees.

[0043] In another exemplary embodiment of the present application, the first detector 10 , the second detector 12 , the third detector 11 and the fourth detector 13 are all photoelectric detectors.

[0044] The working process of the X-ray interferometer for the picometer-level translation stage provided in the present application is as follows: the first beam splitter 2 divides the rays into two beams, one beam reaches the first reflector 5, and reaches the analyzer 8 after being reflected by the first reflector 5. Figure 2 As shown, the first transmitted light and the first reflected light are formed by transmission and reflection through the analyzer 8; the other beam is reflected and transmitted by the second beam splitter 3, and the light reflected by the second beam splitter 3 reaches the analyzer 8, as shown Figure 2As shown, the second transmitted light and the second reflected light are formed by transmission and reflection of the analyzer 8, the second transmitted light and the first reflected light are emitted through the first outgoing light path of the analyzer 8 to generate interference fringes, the first transmitted light and the second reflected light are emitted through the second outgoing light path of the analyzer 8 to generate interference fringes, and the first transmitted light and the second reflected light are emitted through the second outgoing light path of the analyzer 8 to generate interference fringes, which are detected by the first detector 10 and the second detector 12. The moving part of the picometer stage 14 drives the analyzer 8 to move along the X direction, the first detector 10 detects the light intensity of the interference fringes generated by the first outgoing light path of the analyzer 8 during the movement, and the second detector 12 detects the light intensity of the interference fringes generated by the second outgoing light path of the analyzer 8 during the movement, and the processor obtains the displacement of the picometer stage 14 along the X direction based on this.

[0045] Another beam of light transmitted by the second beam splitter 3 reaches the third beam splitter 4, and is split into two beams after being transmitted and reflected by the third beam splitter 4. The beam reflected by the third beam splitter 4 is reflected by the second reflector 6 and reaches the third beam splitter 4. Figure 3 As shown, after being transmitted and reflected by the third beam splitter 4, a third transmitted light and a third reflected light are formed. The light beam transmitted by the third beam splitter 4 is reflected by the third reflector 7 and reaches the third beam splitter 4. Figure 3 As shown, after being transmitted and reflected by the third beam splitter 4, a fourth transmitted light and a fourth reflected light are formed, the third transmitted light and the fourth reflected light are emitted through the first outgoing light path of the third beam splitter 4 to generate interference fringes, the fourth transmitted light and the third reflected light are emitted through the second outgoing light path of the third beam splitter 4 to generate interference fringes, and are detected by the third detector 11 and the fourth detector 13. When the moving part of the picometer stage 14 moves along the Y direction, the third detector 11 detects the intensity of the interference fringes generated by the first outgoing light path of the third beam splitter 4 during the movement, and the fourth detector 13 detects the intensity of the interference fringes generated by the second outgoing light path of the third beam splitter 4 during the movement, and the processor obtains the displacement of the picometer stage 14 along the Y direction based on this.

[0046] The interferometer provided in the present application utilizes two sets of mutually perpendicular crystal planes on the first beam splitter 2 to form diffraction, and divides a beam of light emitted by a light source into two beams along mutually perpendicular directions, which respectively form an interferometer with two sets of crystal planes (the first set of crystal planes includes the first reflector 5, the analyzer 8 and the second beam splitter 3. The second set of crystal planes includes the second beam splitter 3, the second reflector 6, the third beam splitter 4 and the third reflector 7). The two sets of interferometers are in perpendicular directions to achieve displacement measurement in the XY dimensions, and the structure is simple, and only one light source is used to achieve simultaneous measurement of two-dimensional motion.

[0047] An embodiment of the present application also provides a displacement measurement method applied to the above-mentioned X-ray interferometer for the picometer-level translation stage, the displacement measurement method comprising: obtaining the intensity of the interference fringes generated by the outgoing light path of the analyzer after the moving part of the picometer-level translation stage moves and the intensity of the interference fringes generated by the outgoing light path of the third spectrometer.

[0048] The displacement of the picometer stage in the X direction is obtained according to the intensity of the interference fringes generated in the outgoing light path of the analyzer after the moving part of the picometer stage moves.

[0049] The displacement of the picometer-level translation stage in the Y direction is obtained according to the intensity of the interference fringes generated by the outgoing light path of the third beam splitter after the moving part of the picometer-level translation stage moves.

[0050] X-ray interferometry is a method that uses the Laue diffraction phenomenon of X-rays in single crystal silicon to achieve micro-displacement measurement. When a beam of monochromatic X-rays is incident on single crystal silicon at the Bragg angle, three beams of light are formed: direct transmitted light, diffracted light, and anomalous transmitted light. Among them, the diffracted light and the anomalous transmitted light will be reflected by the reflector and eventually meet at the analyzer to form interference fringes. The contrast of the interference fringes is affected by many factors, including the thickness of the beam splitter, reflector, and analyzer, as well as the defocus amount and sideslip angle caused by the movement of the translation stage. The working principle of the X-ray interferometer requires that when the analyzer moves in a direction perpendicular to the diffraction crystal plane, the interference fringes formed by the analyzer will change by one period for each lattice spacing. By calculating the number of periods of the interference fringes generated after the movement and multiplying it by the corresponding lattice spacing, the displacement of the picometer stage can be obtained. Therefore, the displacement of the picometer stage in the X direction is obtained according to the intensity of the interference fringes generated by the outgoing light path of the analyzer after the moving part of the picometer stage moves. Specifically, the period of the interference fringes generated by the outgoing light path of the analyzer after the moving part of the picometer stage moves is calculated according to the intensity of the interference fringes generated by the outgoing light path of the analyzer after the moving part of the picometer stage moves. The displacement of the picometer stage in the X direction is obtained by calculating the product of the period of the interference fringes generated by the outgoing light path of the analyzer after the moving part of the picometer stage moves and the lattice spacing of the analyzer. Similarly, the displacement of the picometer-level translation stage in the Y direction is obtained according to the intensity of the interference fringes generated by the output light path of the third beam splitter after the moving part of the picometer-level translation stage moves. Specifically, the period of the interference fringes generated by the output light path of the third beam splitter after the moving part of the picometer-level translation stage moves is calculated according to the intensity of the interference fringes generated by the output light path of the third beam splitter after the moving part of the picometer-level translation stage moves; the displacement of the picometer-level translation stage in the Y direction is obtained by calculating the product of the period of the interference fringes generated by the output light path of the third beam splitter after the moving part of the picometer-level translation stage moves and the lattice spacing of the third beam splitter.

[0051] The period of the above interference fringes is calculated according to the formula θ / 360, wherein, when calculating the period of the interference fringes generated by the outgoing light path of the analyzer after the moving part of the picometer stage moves along the X direction, θ represents the phase angle of the interference fringes generated by the outgoing light path of the analyzer after the moving part of the picometer stage moves, θ=atan(D1 / D2), D1 represents the intensity of the interference fringes generated by the first outgoing light path of the analyzer detected by the first detector, and D2 represents the intensity of the interference fringes generated by the second outgoing light path of the analyzer detected by the second detector. When calculating the period of the interference fringes generated by the outgoing light path of the third beam splitter after the moving part of the picometer stage moves along the Y direction, in the above formula, θ represents the phase angle of the interference fringes generated by the outgoing light path of the third beam splitter after the moving part of the picometer stage moves, D1 represents the intensity of the interference fringes generated by the first outgoing light path of the third beam splitter detected by the third detector, and D2 represents the intensity of the interference fringes generated by the second outgoing light path of the third beam splitter detected by the fourth detector.

[0052] 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.

[0053] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. An X-ray interferometer for a picometer-level translation stage, characterized in that: The X-ray interferometer for the picometer-level translation stage comprises: An X-ray source, a first beam splitter, a second beam splitter, a third beam splitter, a first reflector, a second reflector, a third reflector, an analyzer, a detection module and a processor; the third reflector and the analyzer are arranged on the moving part of the picometer-level displacement stage; the first beam splitter, the second beam splitter, the third beam splitter, the first reflector, the second reflector, the third reflector and the analyzer are all crystals; The first beam splitter is arranged on the outgoing light path of the X-ray source; the first reflector is arranged on the reflected light path of the first beam splitter; the second beam splitter is arranged on the transmitted light path of the first beam splitter; the reflected light path of the first beam splitter and the transmitted light path of the first beam splitter are perpendicular to each other; the analyzer is arranged on the reflected light path of the first reflector and the reflected light path of the second beam splitter; The third beam splitter is arranged on the transmission light path of the second beam splitter; the second reflector is arranged on the reflection light path of the third beam splitter; the third reflector is arranged on the transmission light path of the third beam splitter; the third beam splitter is arranged on the reflection light path of the second reflector and the reflection light path of the third reflector; The detection module is arranged on the output light path of the analyzer and the output light path of the third spectrometer, and the detection module is used to detect the intensity of the interference fringes generated by the output light path of the analyzer and the intensity of the interference fringes generated by the output light path of the third spectrometer; the processor is connected to the detection module, and the processor is used to calculate the displacement of the picometer-level displacement stage in the X direction and the Y direction according to the intensity of the interference fringes generated by the output light path of the analyzer and the intensity of the interference fringes generated by the output light path of the third spectrometer; the X direction is perpendicular to the Y direction.

2. The X-ray interferometer for a picometer-level translation stage according to claim 1, characterized in that: The X-ray interferometer for the picometer-level translation stage further comprises: A first phase adjuster; the first phase adjuster is arranged on the reflected light path of the first beam splitter; the first reflector is arranged on the output light path of the first phase adjuster.

3. The X-ray interferometer for a picometer-level translation stage according to claim 1, characterized in that: The detection module includes: a first detection unit and a second detection unit; the first detection unit is arranged on the outgoing light path of the analyzer, and the first detection unit is used to detect the intensity of the interference fringes generated by the outgoing light path of the analyzer; the second detection unit is arranged on the outgoing light path of the third spectrometer, and the second detection unit is used to detect the intensity of the interference fringes generated by the outgoing light path of the third spectrometer; the first detection unit includes: a first detector and a second detector; the first detector is arranged on the first outgoing light path of the analyzer, and is used to detect the light intensity of the interference fringes generated by the first outgoing light path of the analyzer, and the second detector is arranged on the second outgoing light path of the analyzer, and is used to detect the light intensity of the interference fringes generated by the second outgoing light path of the analyzer; the second detection unit includes: a third detector and a fourth detector; the third detector is arranged on the first outgoing light path of the third spectrometer, and is used to detect the light intensity of the interference fringes generated by the first outgoing light path of the third spectrometer, and the fourth detector is arranged on the second outgoing light path of the third spectrometer, and is used to detect the light intensity of the interference fringes generated by the second outgoing light path of the third spectrometer.

4. The X-ray interferometer for a picometer-level translation stage according to claim 3, characterized in that: The interference fringes generated by the first outgoing light path of the analyzer and the interference fringes generated by the second outgoing light path of the analyzer have a phase difference of 90 degrees.

5. The X-ray interferometer for a picometer-level translation stage according to claim 3, characterized in that: The interference fringes generated by the first outgoing light path of the third beam splitter and the interference fringes generated by the second outgoing light path of the third beam splitter have a phase difference of 90 degrees.

6. A displacement measurement method for a picometer-level displacement stage, characterized in that: The displacement measurement method for the picometer-level translation stage is applied to the X-ray interferometer for the picometer-level translation stage according to any one of claims 1 to 5, and the displacement measurement method for the picometer-level translation stage comprises: Acquire the intensity of the interference fringes generated by the outgoing light path of the analyzer and the intensity of the interference fringes generated by the outgoing light path of the third beam splitter after the moving part of the picometer-level translation stage moves; The displacement of the picometer stage in the X direction is obtained according to the intensity of the interference fringes generated by the outgoing light path of the analyzer after the moving part of the picometer stage moves; The displacement of the picometer-level translation stage in the Y direction is obtained according to the intensity of the interference fringes generated by the outgoing light path of the third beam splitter after the moving part of the picometer-level translation stage moves.

7. The displacement measurement method for a picometer-level displacement stage according to claim 6, characterized in that: The displacement of the picometer stage in the X direction is obtained according to the intensity of the interference fringes generated by the outgoing light path of the analyzer after the moving part of the picometer stage moves, which specifically includes: Calculating the period of the interference fringes generated by the outgoing light path of the analyzer after the moving part of the picometer stage moves according to the intensity of the interference fringes generated by the outgoing light path of the analyzer after the moving part of the picometer stage moves; The displacement of the picometer stage in the X direction is obtained by calculating the product of the period of the interference fringes generated by the outgoing light path of the analyzer after the moving part of the picometer stage moves and the lattice spacing of the analyzer.

8. The displacement measurement method for a picometer-level displacement stage according to claim 6, characterized in that: The displacement of the picometer-level translation stage in the Y direction is obtained according to the intensity of the interference fringes generated by the outgoing light path of the third beam splitter after the moving part of the picometer-level translation stage moves, specifically including: Calculate the period of the interference fringes generated by the outgoing light path of the third beam splitter after the moving part of the picometer stage moves according to the intensity of the interference fringes generated by the outgoing light path of the third beam splitter after the moving part of the picometer stage moves; The displacement of the picometer stage in the Y direction is obtained by calculating the product of the period of the interference fringes generated by the output light path of the third beam splitter after the moving part of the picometer stage moves and the lattice spacing of the third beam splitter.

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