Nano displacement table based on feedback control of self-tracing grating interferometer and feedback control method

Abstract

The invention discloses a nanometer displacement table based on feedback control of a self-tracing grating interferometer and a feedback control method, and the nanometer displacement table based on feedback control of the self-tracing grating interferometer comprises the self-tracing grating interferometer, a nanometer displacement table, an adjustment table, an upper computer control system, a grating adjustment frame and a self-tracing grating. The self-tracing grating interferometer and the adjusting table are separately placed on the same plane, the nanometer displacement table is fixedly placed on the adjusting table, the upper computer control system is connected with the self-tracing grating interferometer and the nanometer displacement table at the same time and regulates and controls the self-tracing grating interferometer and the nanometer displacement table, and a sample is placed on the nanometer displacement table. The grating adjusting frame is attached to the nanometer displacement table, the self-traceability grating is arranged on the grating adjusting frame, and the self-traceability grating is aligned with the self-traceability grating interferometer. The method has the advantages of being capable of directly tracing on site, convenient to embed, low in environmental change influence, good in repeatability and stability and large in industrial development potential.

Description

Technical Field

[0001] The present invention relates to the field of precision positioning and measurement technology, and in particular to a nanometer displacement stage based on self-traceable grating interferometer feedback control and a feedback control method. Background Art

[0002] Precision positioning and calibration technology is one of the key technologies in precision manufacturing, precision measurement and precision drive. It is widely used in ultra-precision machining, microscopy technology, bioengineering, integrated circuit manufacturing, optical adjustment, scanning tunneling microscope, data storage technology, life and medical sciences, semiconductor manufacturing equipment, optoelectronics and other fields. As one of the key technologies, precision positioning and calibration technology occupies an extremely important position in modern cutting-edge industrial production and scientific research, and influences the development of precision technology in various fields. At present, my country's research on precision positioning and calibration technology and its application is still relatively backward, such as the production of integrated circuit chips and computer chip manufacturing. Therefore, research on precision positioning and calibration technology is conducive to the development of my country's integrated circuit field and is of great significance in promoting the improvement of advanced manufacturing technology.

[0003] As an indispensable component in the research of precision positioning and calibration technology, the nano-displacement stage can not only provide micron-level step displacement with nano-level resolution, but also bear the function of carrying objects. This feature of the nano-displacement stage makes it an important element and one of the important achievements in the research of precision positioning and calibration technology, promoting the development of nano-level high precision in various fields. Therefore, whether it is integrated circuit manufacturing or the development of various ultra-precision processing technologies, the nano-displacement stage system needs to have high resolution, high positioning accuracy, good rigidity, no friction, no creep, good frequency response characteristics, good repeatability and other conditions. These conditions have also become the direction of the development and optimization of the nano-displacement stage. At present, the domestic nano-displacement stage cannot meet all the above conditions, and there are problems such as poor positioning accuracy and positioning repeatability. Compared with foreign nano-displacement stages, there is still a large gap. Therefore, the research on the calibration technology of the nano-displacement stage is of great significance and value.

[0004] Currently, the methods for measuring micro-displacement using commercial nano-displacement stages are divided into the following types: (1) contact measurement using strain gauge sensors; (2) non-contact measurement using instruments such as capacitive sensors, eddy current sensors, and laser interferometers. The contact measurement method using strain gauge sensors has disadvantages such as a greater impact on resolution when the object being measured is small and difficulty in pasting strain gauges. The use of capacitive sensors in non-contact measurement has various problems such as nonlinearity and drift, so calibration is required and traceability is poor; the use of laser interferometers in non-contact measurement has the disadvantage that the instrument is difficult to embed, and the laser wavelength is easily affected by environmental changes, resulting in poor stability and repeatability. The use of ordinary grating interferometers in non-contact measurement also has the disadvantages of requiring calibration and poor traceability. Summary of the invention

[0005] The purpose of the present invention is to provide a nano-displacement stage and a feedback control method based on self-traceable grating interferometer feedback control. The displacement value is measured based on the self-traceable grating interferometer, which can make the value directly traceable to the definition of "meter" and more accurate, not only with the reliability of the measurement value, but also with the stability of the measurement process.

[0006] To achieve the above-mentioned purpose, the present invention provides a nano-displacement stage based on feedback control of a self-traceable grating interferometer, comprising a self-traceable grating interferometer, a nano-displacement stage, an adjustment stage, a host computer control system, a grating adjustment frame and a self-traceable grating, wherein the self-traceable grating interferometer and the adjustment stage are separately placed on the same plane, the nano-displacement stage is fixedly placed on the adjustment stage, the host computer control system simultaneously connects and regulates the self-traceable grating interferometer and the nano-displacement stage, a sample is placed on the nano-displacement stage, the grating adjustment frame is attached to the nano-displacement stage, the self-traceable grating is arranged on the grating adjustment frame, and the self-traceable grating is aligned with the self-traceable grating interferometer.

[0007] Preferably, the nano-displacement stage is a two-dimensional nano-displacement stage, and the nano-displacement stage includes a bow-shaped hinge structure, a piezoelectric ceramic driver and an adapter plate, the bow-shaped hinge structure is symmetrically arranged on the nano-displacement stage, the bow-shaped hinge structure is a flexible hinge, the piezoelectric ceramic driver is arranged on the nano-displacement stage, the adapter plate is arranged at the center of the nano-displacement stage, and the grating adjustment frame is attached directly below the protrusion on the edge of the adapter plate.

[0008] Preferably, the self-traceable grating interferometer is one of a one-dimensional single-frequency self-traceable grating interferometer, a two-dimensional single-frequency self-traceable grating interferometer, a one-dimensional dual-frequency self-traceable grating interferometer and a two-dimensional dual-frequency self-traceable grating interferometer, and the self-traceable grating is one of a one-dimensional self-traceable grating and a two-dimensional self-traceable grating.

[0009] The present invention also provides a feedback control method for a nano-displacement stage based on self-traceable grating interferometer feedback control, comprising the following steps: Calculating the piezoelectric ceramic input voltage of the target displacement according to the target displacement, wherein the target displacement is the displacement expected to be achieved by the nano-displacement stage based on the self-traceable grating interferometer feedback control; Calculating the actual displacement according to the measurement of the interference measurement signal, wherein the interference measurement signal is the interference measurement signal measured by the self-traceable grating interferometer, and the actual displacement is the displacement value actually output by the nano displacement stage; Calculating a displacement deviation value according to the target displacement and the actual displacement; Calculating a target displacement deviation correction amount according to the target displacement, the actual displacement and the displacement deviation value; Determining a piezoelectric ceramic input voltage correction amount of a target displacement according to the target displacement deviation correction amount; Based on the piezoelectric ceramic input voltage correction amount of the target displacement, the nano-displacement stage based on self-traceable grating interferometer feedback control is controlled.

[0010] Preferably, the calculation of the piezoelectric ceramic input voltage for the target displacement includes: determining the piezoelectric ceramic input voltage based on the maximum working range, maximum working voltage and minimum working voltage of the piezoelectric ceramic and according to the required target displacement and the piezoelectric ceramic voltage-displacement conversion relationship.

[0011] Preferably, the calculation of the actual displacement includes: based on the interference measurement signal measured by the self-traceable grating interferometer, after conversion through ADC, passing through the host computer control system through signal filtering, differential amplification, orthogonalization processing and regularization processing, and finally calculating the corresponding actual displacement value using the inverse tangent method.

[0012] Preferably, calculating the displacement deviation value according to the target displacement and the actual displacement includes: based on the actual displacement value and the target displacement value obtained by the self-traceable grating interferometer through the host computer control system, calculating the difference between the two as the displacement deviation value.

[0013] Preferably, the calculating the target displacement deviation correction amount according to the target displacement, the actual displacement and the displacement deviation value includes: calculating the displacement deviation correction amount based on the proportional relationship between the actual displacement value and the target displacement value and the displacement deviation value.

[0014] Preferably, determining the piezoelectric ceramic input voltage correction amount for the target displacement based on the target displacement deviation correction amount includes: calculating the piezoelectric ceramic input voltage correction amount for the target displacement based on the calculated displacement deviation correction amount and the piezoelectric ceramic maximum working range, maximum working voltage, minimum working voltage and voltage-displacement conversion relationship.

[0015] Preferably, the piezoelectric ceramic input voltage correction amount based on the target displacement controls the nano-displacement stage based on the feedback control of the self-traceable grating interferometer, including: determining the correction coefficient of the PID parameter according to the piezoelectric ceramic input voltage correction amount and the piezoelectric ceramic input voltage; controlling the nano-displacement stage based on the feedback control of the self-traceable grating interferometer according to the target displacement deviation correction amount and the correction coefficient of the PID parameter.

[0016] Therefore, the present invention adopts the above-mentioned nano-displacement stage and feedback control method based on self-traceable grating interferometer feedback control, which has the following beneficial effects: (1) The self-traceable grating interferometer uses a self-traceable grating as the displacement measurement reference element, so that the displacement measurement value of the vibration calibration equipment based on the self-traceable grating does not need external calibration, but can be directly traced to the pitch value of the self-traceable grating, and at the same time directly traced to the atomic transition energy level constant; not only does it greatly shorten the traceability chain of the measured value, but it also makes the displacement based on the grating period, greatly reducing the influence of ambient temperature, pressure, and humidity, and improving the environmental tolerance; at the same time, the self-traceable grating interferometer has a simple and compact optical structure, and can greatly reduce the system volume through integrated design, which is conducive to the research and development of various industrial portable products.

[0017] (2) The value transfer chain of the present invention is "meter → self-traceable grating → nanometer displacement stage", while the original traceability system of the nanometer displacement stage is "meter → 633nm wavelength national standard → 633nm wavelength working standard → metrology calibration equipment → nanometer displacement stage". The value transfer chain of the present invention is short, the error accumulation is small, and the calibration efficiency is high. It is suitable for the metrology industrialization of integrated circuit micro-nano detection equipment and can accelerate the industrialization transformation of high-precision metrology detection equipment.

[0018] (3) The present invention can use a high-line density self-traceable grating period as a displacement measurement benchmark. The original signal period generated by interference is much smaller than the signal period of 250-350nm corresponding to the existing laser wavelength benchmark. Combining electronic subdivision and signal error compensation methods can greatly improve the resolution of the displacement signal, thereby improving the displacement accuracy of the nano-displacement stage.

[0019] (4) The present invention uses a real grating as a displacement measurement reference, which effectively avoids the interference of air factors on the measurement data. Under the same measurement environment, it is more stable than the measurement equipment using the laser wavelength as the reference, the measured data is more comparable, the measurement repeatability is greater, and it is easier to embed than the laser interferometer.

[0020] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of a nano-displacement stage based on self-traceable grating interferometer feedback control according to an embodiment of the present invention; Figure 2 A bottom view of the nano-translation stage according to an embodiment of the present invention; Figure 3 is a schematic structural diagram of a nano-displacement stage according to an embodiment of the present invention; Figure 4 is a flow chart of a feedback control method according to an embodiment of the present invention; Figure 5A schematic diagram of a two-dimensional displacement mode of a nano-displacement stage based on feedback control of a self-traceable grating interferometer according to an embodiment of the present invention; Figure 6 Schematic diagram of the preparation process of the self-traceable grating according to an embodiment of the present invention; Figure 7 This is a diagram showing the triangular wave operation results of a nano-displacement stage based on self-traceable grating interferometer feedback control in a range of 20 μm according to an embodiment of the present invention; Reference numerals 1. Self-traceable grating interferometer; 2. Nano-displacement stage; 21. Bow hinge structure; 22. Piezoelectric ceramic driver; 23. Adapter plate; 3. Adjustment table; 4. Host computer control system; 5. Grating adjustment frame; 6. Sample; 7. Self-traceable grating. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0023] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0024] Example like Figure 1-2 As shown, the present invention provides a nano-displacement stage based on feedback control of a self-traceable grating interferometer, comprising a self-traceable grating interferometer 1, a nano-displacement stage 2, an adjustment stage 3, a host computer control system 4, a grating adjustment frame 5 and a self-traceable grating 7. The self-traceable grating interferometer 1 and the adjustment stage 3 are placed separately on the same plane, the nano-displacement stage 2 is fixedly placed on the adjustment stage 3, and the adjustment stage 3 is mainly used for fixing the nano-displacement stage 2 and aligning the self-traceable grating interferometer 1. The host computer control system 4 simultaneously connects and regulates the self-traceable grating interferometer 1 and the nano-displacement stage 2, a sample 6 is placed on the nano-displacement stage 2, and the grating adjustment frame 5 is attached to the nano-displacement stage 2. The self-traceable grating 7 is arranged on the grating adjustment frame 5, and the self-traceable grating 7 is aligned with the self-traceable grating interferometer 1.

[0025] like Figure 3 As shown, the nano-displacement stage 2 is a two-dimensional nano-displacement stage. The nano-displacement stage 2 includes a bow-shaped hinge structure 21, a piezoelectric ceramic driver 22 and an adapter plate 23. The bow-shaped hinge structure 21 is symmetrically arranged on the nano-displacement stage 2. The bow-shaped hinge structure 21 is a flexible hinge. The piezoelectric ceramic driver 22 is arranged on the nano-displacement stage 2. The adapter plate 23 is arranged at the center of the nano-displacement stage. The grating adjustment frame 5 is attached to the right below the edge protrusion of the adapter plate 23. The purpose is to make the self-traceable grating 7 coincide with the motion axis of the nano-displacement stage 2, thereby eliminating the Abbe error. Through the parallel combination of the bow-shaped hinge structure 21, the piezoelectric ceramic driver 22 can drive the bow-shaped hinge structure 21 to deform and generate nano-displacement. The adapter plate 23 is used to carry the sample. The piezoelectric ceramic driver 22 outputs a displacement signal to control the movement of the nano-displacement stage 2, and the method is to adjust the input voltage value of the piezoelectric ceramic driver 22 through the host computer control system 4.

[0026] The self-traceable grating 7 determines the characteristic parameters of the grating through the transition frequency of chromium atoms, and is one of a one-dimensional self-traceable grating and a two-dimensional self-traceable grating.

[0027] The self-traceable grating interferometer 1 refers to an interferometer that uses the self-traceable grating 7 as a displacement scale, utilizes the frequency difference of two beams of light generated by the Doppler effect of the grating movement, generates an interference measurement signal after beam combination, and converts the signal into a displacement based on the grating period, thereby realizing micro-nano scale measurement. The displacement can be directly traced back to the definition of "meter" because the self-traceable grating 7 has an extremely short traceability chain. The displacement measurement method implemented by the self-traceable grating interferometer 1 includes: the X-axis length value is obtained by measuring the self-traceable grating 7 displacement of the X-axis of the nano displacement stage 2 by the self-traceable grating interferometer 1, and the Y-axis length value is obtained by measuring the self-traceable grating 7 displacement of the Y-axis of the nano displacement stage 2 by the self-traceable grating interferometer 1.

[0028] The nanometer displacement stage 2 based on the self-traceable grating interferometer 1 can select the two-dimensional measurement method of the self-traceable grating interferometer 1. Before the measurement, it can be calibrated by the self-traceable grating interferometer 1 in advance. The measurement method is the same as the calibration method. Figure 5 As shown, two-dimensional means using two self-traceable grating interferometers 1 to simultaneously measure the X-axis and Y-axis of the XY nano-displacement stage 2, and adjusting the corresponding displacement through the host computer control system 4. Figure 5 Alignment reference of self-traceable grating interferometer 1 and self-traceable grating 7 Figure 1 .

[0029] The self-traceable grating interferometer 1 can be divided into homodyne, heterodyne, self-mixed one-dimensional and two-dimensional self-traceable grating interferometers according to structure, principle and measurement method. The homodyne self-traceable grating interferometer is a typical representative of the self-traceable grating interferometer 1. In the present embodiment, the self-traceable grating interferometer 1 is one of a one-dimensional single-frequency self-traceable grating interferometer, a two-dimensional single-frequency self-traceable grating interferometer, a one-dimensional dual-frequency self-traceable grating interferometer and a two-dimensional dual-frequency self-traceable grating interferometer. In the present embodiment, a homodyne one-dimensional self-traceable grating interferometer is preferred, and its signal processing method includes: after signal filtering, differential amplification, orthogonalization processing and regularization processing, the displacement value is finally calculated by the inverse tangent method.

[0030] The self-traceable grating 7 refers to a grating whose characteristic parameters (such as period) can be directly traced back to certain natural reference gratings. Atomic lithography technology is used to heat and sublimate metal materials to a gas state in a vacuum environment and spray them in an effusion manner. The sprayed atomic beam passes through a frequency-stabilized laser to lock the laser wavelength to the transition frequency of two energy levels of metal atoms. The sprayed periodically distributed atoms are deposited on a suitably placed substrate to form a grating structure. The grating period can be directly traced back to the transition frequency of two energy levels of metal atoms. The chromium atomic lithography grating that can be traced back to the transition frequency of chromium atoms is a typical representative of the self-traceable grating 7, which can be divided into one-dimensional chromium atomic lithography grating and two-dimensional chromium atomic lithography grating. In this embodiment, a one-dimensional chromium atomic lithography grating is preferred. Figure 6 As shown, the chromium transition frequency is selected ( 7 S3 → 7 P4) is used as a natural reference, and the laser wavelength is strictly locked at the wavelength corresponding to the transition frequency (425.55nm), so that the collimated chromium atomic beam is orthogonally deposited on the substrate through the standing wave field formed by the above wavelengths. The chromium atoms will be gathered to the antinode or node position corresponding to the standing wave field, forming a periodic parallel grating structure on the substrate. The grating line density of the chromium atom lithography is 4700 lines / mm, the grating spacing is 212.8nm, and the range can reach 10mm.

[0031] The self-traceable grating interferometer detects and feedback controls the movement of the nano-stage in real time under the condition of 20μm range triangle wave motion. The displacement results are as follows: Figure 7 The maximum displacement range of the piezoelectric ceramic used in this embodiment is 25 μm, the input voltage range is 0-150 V, and the sensor uses a one-dimensional self-traceable grating interferometer.

[0032] The method for using a nano-displacement stage based on feedback control of a self-traceable grating interferometer comprises the following specific steps: when achieving nano-displacement of a sample 6, first, align the self-traceable grating 7 on the nano-displacement stage 2 with the self-traceable grating interferometer 1; then, the nano-displacement stage 2 carrying the sample 6 inputs a signal through the host computer control system 4 to cause the piezoelectric ceramic driver 22 to move the X-axis or Y-axis by a certain displacement; at the same time, the self-traceable grating interferometer 1 measures the displacement in real time, and inputs the measured displacement value into the host computer control system 4; then, two-dimensional regulation is performed through the host computer control system 4, so that the sample 6 finally obtains an actual displacement that matches the target displacement.

[0033] The displacement is measured online by a self-traceable grating interferometer and the host computer feedback system uses a feedback control method to eliminate the hysteresis and creep of the piezoelectric ceramics, the crosstalk between different axes caused by the flexible hinge and the overall structure of the nano-displacement stage it constitutes, the resonance generated when the nano-displacement stage 2 is working, the environmental noise and vibration, etc., so that the sample can obtain the expected displacement.

[0034] like Figure 4 As shown, the present invention also provides a feedback control method of a nano-displacement stage based on self-traceable grating interferometer feedback control, comprising the following steps: According to the target displacement, the piezoelectric ceramic (i.e., piezoelectric ceramic driver) input voltage of the target displacement is calculated, and the target displacement is the displacement expected to be achieved by the nano-displacement stage based on the feedback control of the self-traceable grating interferometer; The actual displacement is calculated according to the measurement of the interference measurement signal, the interference measurement signal is the interference measurement signal measured by the self-traceable grating interferometer, and the actual displacement is the displacement value actually output by the nano-displacement stage; Calculate the displacement deviation value according to the target displacement and the actual displacement; Calculate the target displacement deviation correction amount according to the target displacement, the actual displacement and the displacement deviation value; Determine the piezoelectric ceramic input voltage correction amount of the target displacement according to the target displacement deviation correction amount; The nanometer displacement stage based on the feedback control of the self-traceable grating interferometer is controlled based on the piezoelectric ceramic input voltage correction amount of the target displacement.

[0035] In this embodiment, calculating the piezoelectric ceramic input voltage for the target displacement includes: determining the piezoelectric ceramic input voltage based on the maximum working range, maximum working voltage and minimum working voltage of the piezoelectric ceramic according to the required target displacement and the piezoelectric ceramic voltage-displacement conversion relationship.

[0036] In this embodiment, the calculation of the actual displacement includes: based on the interference measurement signal measured by the self-traceable grating interferometer 1, after ADC conversion, through the host computer control system 4, signal filtering, differential amplification, orthogonalization processing and regularization processing, and finally using the inverse tangent method to calculate the corresponding actual displacement value.

[0037] In this embodiment, the displacement deviation value is calculated according to the target displacement and the actual displacement, including: based on the actual displacement value and the target displacement value obtained by the self-traceable grating interferometer 1 through the host computer control system 4, the difference between the two is calculated as the displacement deviation value.

[0038] In this embodiment, the target displacement deviation correction amount is calculated according to the target displacement, the actual displacement and the displacement deviation value, including: based on the proportional relationship between the actual displacement value and the target displacement value and the displacement deviation value, the displacement deviation correction amount is calculated through certain mathematical operations.

[0039] In this embodiment, the piezoelectric ceramic input voltage correction amount of the target displacement is determined according to the target displacement deviation correction amount, including: based on the calculated displacement deviation correction amount and the piezoelectric ceramic maximum working range, maximum working voltage, minimum working voltage and voltage-displacement conversion relationship, the piezoelectric ceramic input voltage correction amount of the target displacement is calculated.

[0040] In this embodiment, a nano-displacement stage based on self-traceable grating interferometer feedback control is controlled based on a piezoelectric ceramic input voltage correction amount of a target displacement, including: determining a correction coefficient of a PID parameter based on the piezoelectric ceramic input voltage correction amount and the piezoelectric ceramic input voltage; and controlling the nano-displacement stage based on self-traceable grating interferometer feedback control based on a target displacement deviation and the correction coefficient of the PID parameter.

[0041] Therefore, the present invention adopts the above-mentioned nano-displacement stage based on self-traceable grating interferometer feedback control and its use method. The core lies in using the self-traceable grating interferometer as the measurement standard of displacement, which can realize on-site real-time traceable calibration or traceable control of the displacement of the nano-displacement stage through the host computer control system.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A nanometer displacement stage based on self-traceable grating interferometer feedback control, characterized in that: The invention comprises a self-traceable grating interferometer, a nano-displacement stage, an adjustment stage, a host computer control system, a grating adjustment frame and a self-traceable grating. The self-traceable grating interferometer and the adjustment stage are separately placed on the same plane, the nano-displacement stage is fixedly placed on the adjustment stage, the host computer control system simultaneously connects and regulates the self-traceable grating interferometer and the nano-displacement stage, a sample is placed on the nano-displacement stage, the grating adjustment frame is attached to the nano-displacement stage, the self-traceable grating is arranged on the grating adjustment frame, and the self-traceable grating is aligned with the self-traceable grating interferometer.

2. The nano-displacement stage based on self-traceable grating interferometer feedback control according to claim 1, characterized in that: The nano-displacement stage is a two-dimensional nano-displacement stage, comprising a bow-shaped hinge structure, a piezoelectric ceramic driver and an adapter plate. The bow-shaped hinge structure is symmetrically arranged on the nano-displacement stage, the bow-shaped hinge structure is a flexible hinge, the piezoelectric ceramic driver is arranged on the nano-displacement stage, the adapter plate is arranged at the center of the nano-displacement stage, and the grating adjustment frame is attached directly below the protrusion on the edge of the adapter plate.

3. The nano-displacement stage based on self-traceable grating interferometer feedback control according to claim 1, characterized in that: The self-traceable grating interferometer is one of a one-dimensional single-frequency self-traceable grating interferometer, a two-dimensional single-frequency self-traceable grating interferometer, a one-dimensional dual-frequency self-traceable grating interferometer and a two-dimensional dual-frequency self-traceable grating interferometer, and the self-traceable grating is one of a one-dimensional self-traceable grating and a two-dimensional self-traceable grating.

4. A feedback control method for a nano-displacement stage based on feedback control of a self-traceable grating interferometer, applied to a nano-displacement stage based on feedback control of a self-traceable grating interferometer as claimed in any one of claims 1 to 3, characterized in that: The following steps are involved: Calculating the piezoelectric ceramic input voltage of the target displacement according to the target displacement, wherein the target displacement is the displacement expected to be achieved by the nano-displacement stage based on the self-traceable grating interferometer feedback control; Calculating the actual displacement according to the measurement of the interference measurement signal, wherein the interference measurement signal is the interference measurement signal measured by the self-traceable grating interferometer, and the actual displacement is the displacement value actually output by the nano displacement stage; Calculating a displacement deviation value according to the target displacement and the actual displacement; Calculating a target displacement deviation correction amount according to the target displacement, the actual displacement and the displacement deviation value; Determining a piezoelectric ceramic input voltage correction amount of a target displacement according to the target displacement deviation correction amount; Based on the piezoelectric ceramic input voltage correction amount of the target displacement, the nano-displacement stage based on self-traceable grating interferometer feedback control is controlled.

5. The feedback control method of a nano-displacement stage based on self-traceable grating interferometer feedback control according to claim 4, characterized in that: The calculation of the piezoelectric ceramic input voltage for the target displacement includes: determining the piezoelectric ceramic input voltage based on the maximum working range, maximum working voltage and minimum working voltage of the piezoelectric ceramic and according to the required target displacement and the piezoelectric ceramic voltage-displacement conversion relationship.

6. The feedback control method of a nano-displacement stage based on self-traceable grating interferometer feedback control according to claim 5, characterized in that: The calculation of the actual displacement includes: based on the interference measurement signal measured by the self-traceable grating interferometer, after ADC conversion, through the host computer control system, signal filtering, differential amplification, orthogonalization processing and regularization processing, and finally using the inverse tangent method to calculate the corresponding actual displacement value.

7. The feedback control method of a nano-displacement stage based on self-traceable grating interferometer feedback control according to claim 6, characterized in that: The method of calculating the displacement deviation value according to the target displacement and the actual displacement includes: calculating the difference between the actual displacement value and the target displacement value obtained by the self-traceable grating interferometer through the host computer control system as the displacement deviation value.

8. The feedback control method of a nano-displacement stage based on self-traceable grating interferometer feedback control according to claim 7, characterized in that: Calculating the target displacement deviation correction amount according to the target displacement, the actual displacement and the displacement deviation value includes: calculating the displacement deviation correction amount based on the proportional relationship between the actual displacement value and the target displacement value and the displacement deviation value.

9. The feedback control method of a nano-displacement stage based on self-traceable grating interferometer feedback control according to claim 8, characterized in that: Determining the piezoelectric ceramic input voltage correction amount of the target displacement according to the target displacement deviation correction amount includes: calculating the piezoelectric ceramic input voltage correction amount of the target displacement based on the calculated displacement deviation correction amount and the piezoelectric ceramic maximum working range, maximum working voltage, minimum working voltage and voltage-displacement conversion relationship.

10. The feedback control method of a nano-displacement stage based on self-traceable grating interferometer feedback control according to claim 9, characterized in that: The piezoelectric ceramic input voltage correction amount based on the target displacement controls the nano-displacement stage based on the feedback control of the self-traceable grating interferometer, including: determining the correction coefficient of the PID parameter according to the piezoelectric ceramic input voltage correction amount and the piezoelectric ceramic input voltage; and controlling the nano-displacement stage based on the feedback control of the self-traceable grating interferometer according to the target displacement deviation correction amount and the correction coefficient of the PID parameter.

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