阅读说明：本技术 一种制造微纳米台阶阵列结构的离子束抛光加工方法 (Ion beam polishing processing method for manufacturing micro-nano step array structure ) 是由 李平 段辉高 王兆龙 于 2020-02-29 设计创作，主要内容包括：本发明公开了一种制造微纳米台阶阵列结构的离子束抛光加工方法,该方法首先准备一片衬底,在衬底上沉积一定微纳米厚度的电介质层薄膜,并对电介质层薄膜的厚度与表面形貌进行观测；通过单点驻留抛光试验确定电介质层薄膜的离子束抛光工艺去除函数；根据单点驻留去除函数确定等效的光栅扫描去除函数与微纳米台阶高度,并采用栅格路径扫描法对电介质层薄膜开展不同扫描速度条件下的分区域加工；利用检测装置对单个微纳米台阶的高度、面形精度和表面粗糙度进行检测并判别；最后将微纳米台阶加工信息保存至数据库。本方法不仅工艺简单、可操作性强,适用于电介质层薄膜表面的大面积、阶跃式微纳米台阶阵列的高效率超精密制造。(The invention discloses an ion beam polishing processing method for manufacturing a micro-nano step array structure, which comprises the steps of firstly preparing a substrate, depositing a dielectric layer film with certain micro-nano thickness on the substrate, and observing the thickness and the surface appearance of the dielectric layer film; determining an ion beam polishing process removal function of the dielectric layer film through a single-point resident polishing test; determining an equivalent raster scanning removal function and the height of the micro-nano step according to the single-point resident removal function, and performing regional processing on the dielectric layer film under the conditions of different scanning speeds by adopting a raster path scanning method; detecting and judging the height, surface shape precision and surface roughness of a single micro-nano step by using a detection device; and finally, storing the micro-nano step processing information to a database. The method is simple in process and strong in operability, and is suitable for high-efficiency ultra-precise manufacturing of large-area step-type micro-nano step arrays on the surface of the dielectric layer film.)

1. An ion beam polishing processing method for manufacturing a micro-nano step array structure is characterized in that: firstly, preparing a substrate, depositing a dielectric layer film on the substrate, and observing the thickness and the surface appearance of the dielectric layer film; determining an ion beam polishing process removal function of the dielectric layer film through a single-point resident polishing test; determining an equivalent raster scanning removal function and the height of the micro-nano step according to the single-point resident removal function, and performing regional processing on the dielectric layer film under the conditions of different scanning speeds by adopting a raster path scanning method; detecting the height, surface shape precision and surface roughness of the single micro-nano step by using a detection device, judging whether the detection result meets the machining precision requirement, and if not, re-adopting an ion beam polishing process to shape and machine the single micro-nano step; and if the micro-nano step machining information is consistent, storing the micro-nano step machining information into a database.

2. The ion beam polishing method for manufacturing the micro-nano step array structure according to claim 1, wherein: the substrate material is silicon wafer or quartz glass.

3. The ion beam polishing method for manufacturing the micro-nano step array structure according to claim 1, wherein: after the dielectric layer thin film deposition is finished, measuring the thickness of the thin film by using a spectroscopic ellipsometer, and analyzing the deposition error of the measured data; and observing the surface appearance of the prepared dielectric layer film by using a field emission scanning electron microscope.

4. The ion beam polishing method for manufacturing the micro-nano step array structure according to claim 1, wherein: developing a dielectric layer film single-point resident polishing test on an ion beam polishing machine tool to obtain a removal function A (x, y); the experiment was carried out based on several ion beam process parameters: ion beam incident angle (θ), ion beam energy (E), ion beam dwell time (T)_e) And the distance (D) between the ion source and the target surface; after the test, the profile of the single-point pit is detected by a profiler, then a Gaussian function is obtained by fitting the profile of the center of the removed single-point pit, and the average removal rate (R) of the surface is estimated according to the Gaussian function_surf) And removing the size of the function half-peak wide beam diameter.

5. The ion beam polishing method for manufacturing the micro-nano step array structure according to claim 1, wherein: determining an equivalent raster scanning removal function and the height of the micro-nano step based on a processing result of an ion beam single-point resident polishing test; planning a process path and a scanning speed of ion beam polishing processing; wherein the ion beam process path adopts raster path scanning mode with scanning step T_SShould follow the following principles:

in the formula f_cIs the cut-off frequency of the removal function; the width of the Gaussian-like removal function is d_6σThen the cut-off frequency of the removal function is expressed as:

the method comprises the steps of carrying out regional processing on a dielectric layer film material by adopting a raster path scanning method under the condition of different scanning speeds, namely, circularly moving an ion beam on the surface of a defined region in a raster scanning mode, and finally forming micro-nano step array structures with different heights.

6. The ion beam polishing method for manufacturing the micro-nano step array structure according to claim 1, wherein: adopting a contourgraph, a laser interferometer and an atomic force microscope detection device to detect the height, the surface shape precision and the surface roughness of a single micro-nano step, and judging whether the detection result meets the processing precision requirement or not: the error of the step height is less than or equal to +/-5 nm, the surface shape precision PV is less than or equal to lambda/10, and the surface roughness Ra is less than or equal to 1 nm; if not, the single micro-nano step is subjected to shape modification processing by adopting the ion beam polishing process again according to the detection result.

7. The ion beam polishing method for manufacturing the micro-nano step array structure according to claim 6, wherein: in the shape modification processing, shape modification process parameters are selected, the shape modification processing is carried out on a single micro-nano step with the detection result not meeting the requirements on an ion beam polishing machine tool, and after the shape modification processing is finished, the micro-nano step is detected and evaluated by using related detection equipment.

Technical Field

The invention belongs to the field of micro-nano manufacturing, and particularly relates to an ion beam polishing processing method for manufacturing a step-type micro-nano step array structure on the surface of a large-area dielectric layer film.

Background

With the continuous development of modern optical technology, functional optoelectronic devices have put higher and higher requirements on the performance of dielectric thin films (optical thin films). Various micro-nano structures are introduced into the dielectric layer film, and the functions of the functional photoelectric device system can be further regulated, controlled and expanded by combining the refraction and diffraction effects of the micro-nano structures with the interference effect of the dielectric layer film. For example, the monolithic stepped micro-nano step array structure is very important to be applied to functional photoelectric devices such as holographic lenses, Fresnel zone plates, micro lenses, integrated optical filters, plasmon nano optics and the like due to the integration of information with different step heights.

The thickness of the dielectric layer film is generally in the micron or even nanometer level, and the height of the monolithically integrated micro-nano step array needs to show step-like gradient change, so the manufacturing process of the dielectric layer film faces a great challenge. The manufacture of the prior step-type micro-nano step array structure is mostly realized by technologies such as ultraviolet lithography, pixelized mask lithography, electron beam gray scale exposure and electron beam ice etching, but the application range of the prior step-type micro-nano step array structure has larger limitation. On one hand, the photolithography technology is difficult to realize the fabrication of a step array structure on a large-area non-resist material. On the other hand, although some researchers propose an overlay method combining a lithography process and an ion beam etching process, which can realize large-area, high-precision and step-type micro-nano step array structure manufacturing on non-resist materials, the method has the problems of complex overall process, excessively high mask curing and processing cost and the like. For example, the patent application number 200910207134.X relates to a preparation method of a monolithic integrated detector array with a multi-wavelength processing function, and a Fabry-Perot resonant cavity structure with a multi-step structure is realized on a GaAs-based substrate through a multiple etching process and a secondary epitaxial growth process. In addition, a patent (application number: 201410519408.X) and a patent (application number: 201410519354.7) propose a method for manufacturing a high-precision multi-step micro-lens array, and solve the problems of high requirement on manufacturing precision of operators and operating equipment, low yield and high cost of the existing method to a certain extent.

Currently, ion beam polishing has been developed as a mature technology in the manufacturing process chain of ultra-precision optical parts. The basic principle is that in a vacuum environment, ion beams emitted by an ion source bombard the surface of a workpiece, and the surface material of the workpiece is removed in a definite manner by utilizing the physical sputtering effect generated by the ion bombardment. The ion beam polishing processing has the manufacturing capability of nano scale and nano precision magnitude, is a processing mode with high certainty, high stability and non-contact, is not only suitable for the ultra-precision processing of planar optical parts in modern optics, but also has huge application markets in parts which are difficult to process, such as aspheric surfaces, free-form surfaces, special-shaped/thin type parts and the like. Therefore, the ion beam polishing processing technology is applied to the manufacture of the large-area and step-type micro-nano step array structure of the dielectric layer film, and has high feasibility and important engineering application value.

Disclosure of Invention

The purpose of the invention is: aiming at the problems that the existing step-type micro-nano step array structure depends on photoresist materials, the whole process is complex, the curing and processing cost of a mask is too high, the micro-nano structure is extremely difficult to manufacture on the surface of a dielectric layer film and the like, an ion beam polishing processing method of a large-area step-type micro-nano step array structure suitable for the dielectric layer film is developed, and the requirements of high-efficiency, ultra-precision and low-cost manufacture of the micro-nano step array are met.

The technical scheme adopted by the invention is as follows: an ion beam polishing processing method for manufacturing a micro-nano step array structure comprises the steps of firstly preparing a substrate with high surface precision and high surface quality; then, depositing a dielectric layer film with a certain micro-nano thickness on the substrate, and observing the thickness and the surface appearance of the dielectric layer film; determining an ion beam polishing process removal function of the dielectric layer film through a single-point resident polishing test; determining an equivalent raster scanning removal function and the height of the micro-nano step according to the single-point resident removal function, and performing regional processing on the dielectric layer film under the conditions of different scanning speeds by adopting a raster path scanning method; detecting the height, surface shape precision and surface roughness of the single micro-nano step by using a detection device, judging whether the detection result meets the machining precision requirement, and if not, re-adopting an ion beam polishing process to shape and machine the single micro-nano step; and finally, storing the micro-nano step processing information to a database.

The specific technical scheme comprises the following key points:

(1) substrate preparation

In order to ensure the reliability and stability of the high-precision manufacturing process of the micro-nano step array structure, certain requirements are required to be provided for the surface precision and the surface quality of the customized large-area substrate material, for example, a silicon wafer substrate with the size phi of 50.8 × 2mm and a quartz glass substrate with the size 55mm × 55mm × 2mm are taken as examples, the surface shape precision PV of the silicon wafer substrate and the quartz glass substrate in the full aperture range is required to be less than or equal to lambda/10, the surface roughness Ra is less than or equal to 1nm, and meanwhile, the defects of cracks, scratches, pits and the like cannot be allowed to appear on the surface (2) dielectric layer film deposition and film thickness and appearance observation

The dielectric layer thin film material with the thickness within the optical thickness range (1000 nm) is deposited on the prepared substrate material through an electron beam evaporation system (Kurt J, L esker, L ab-L ine), the deposition rate is required to be stable in the thin film deposition process, the thin film thickness is uniform, and no surface stress is released after deposition.

(3) Dielectric layer film single point dwell polishing test

Developing dielectric on ion beam polisher bedAnd (3) obtaining a removal function A (x, y) by a single-point residence polishing test of the thin film of the stratum. The experiment will develop a systematic study based on several ion beam process parameters: ion beam incident angle (θ), ion beam energy (E), ion beam dwell time (T)_e) And the distance (D) between the ion source and the target surface. The profile of the single-point pits after the test was detected by a profiler (PGI1240, TaylorHobson), and then a Gaussian function was fitted from the profile of the center of the removed single-point pits, and the surface average removal rate (R) was estimated therefrom_surf) And removing the size of the function full width at half maximum beam diameter (FWHM).

(4) Ion beam polishing micro-nano step array structure

In order to realize large-area and high-efficiency polishing processing of a step-type micro-nano step array structure, an equivalent raster scanning removal function and micro-nano step height can be determined based on a processing result of an ion beam single-point residence polishing test; meanwhile, the process path and the scanning speed of the ion beam polishing process need to be planned. Wherein the ion beam process path adopts raster path scanning mode with scanning step T_SShould follow the following principles:

in the formula f_cTo remove the cut-off frequency of the function. The width of the Gaussian-like removal function is d_6σThen the cut-off frequency of the removal function can be expressed as:

and then, performing regional processing on the dielectric layer film material by adopting a raster path scanning method under the condition of different scanning speeds, namely, circularly moving the ion beam on the surface of the defined region in a raster scanning mode, and finally forming the micro-nano step array structures with different heights.

(5) Micro-nano step array structure processing result detection

Detecting the height, the surface shape precision and the surface roughness of a single micro-nano step by using detection devices such as a contourgraph (PGI1240, Taylor Hobson), a laser interferometer (GPI (TM) XP D, Zygo), an atomic force microscope (MultiMode8, Bruker) and the like, and judging whether the detection result meets the machining precision requirement or not: the error of the step height is less than or equal to +/-5 nm, the surface shape precision PV is less than or equal to lambda/10, and the surface roughness Ra is less than or equal to 1 nm. If not, the single micro-nano step is subjected to shape modification processing by adopting the ion beam polishing process again according to the detection result.

(6) Single micro-nano step ion beam shape-modifying processing

And selecting proper shape modification process parameters, performing shape modification processing on the single micro-nano step with the detection result not meeting the requirement on an ion beam polishing machine, and detecting and evaluating the single micro-nano step by using related detection equipment after the shape modification processing is finished. And finally, storing the micro-nano step processing information to a database.

According to the technical scheme, the manufacturing method of the micro-nano step array structure provided by the disclosure at least has the following beneficial effects:

1. the method is suitable for processing any material. Photon beam lithography and electron beam lithography are not suitable for fabrication of stepped micro-nano step array structures on non-resist materials, such as metals, ceramics, glass, media, and the like. The ion beam polishing is not limited by the material property of the processing object, and can be applied to the processing of any material.

2. Large area and high efficiency. The micro-nano step array structure processed by the existing manufacturing method is small in overall size (generally below millimeter level), low in processing efficiency and incapable of realizing large-area manufacturing. In comparison, the ion beam polishing adopts a processing mode of a raster scanning mode, the material removal rate is high, the large-area manufacturing of a monolithic integrated micro-nano step array structure can be realized, the macroscopic overall size can reach 100mm on the premise of ensuring the optical thickness in the height direction, and the size of a single pixel can reach 50 microns.

3. And (4) high-precision manufacturing. The existing method has more factors influencing the manufacturing precision of the micro-nano step array structure, such as uncontrollable light intensity, mask plate pixel solidification, proximity effect of electron beam exposure, insufficient material determinacy removed by ion beam etching and the like in the process of photon beam processing, and the processed step has insufficient precision such as surface shape precision, surface roughness, size precision and the like. Compared with the prior art, the ion beam polishing has determinacy and stability, and can repair and process a single nano step with insufficient processing precision, so that the high-precision manufacturing of the micro-nano step array structure is easily ensured.

4. The cost is low. The existing processing method has the problems of higher mask customization cost, expensive electron beam lithography equipment and focused ion beam lithography equipment, complex overall process of the alignment method, low processing cost performance and the like, so that the product processing cost is higher, and the method is particularly prominent when the large-area micro-nano step array structure is manufactured.

Drawings

These and other features, aspects and advantages of the present invention will now be described, as will become better understood from the following detailed description when read in conjunction with the accompanying drawings, wherein:

FIG. 1 is a flow chart of a manufacturing process of a micro-nano step array structure on the surface of a dielectric layer film.

FIG. 2 is a schematic diagram of a single point resident polishing process for a thin film of dielectric layer.

FIG. 3 is a schematic diagram of a stepped micro-nano step array structure processing of a dielectric layer film.

Detailed Description

The following detailed description of the embodiments of the present invention with reference to the drawings shows detailed embodiments and specific operations, but the scope of the present invention is not limited to the following embodiments. The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. The embodiment comprises the following steps:

as shown in fig. 1: firstly, preparing a substrate with high surface precision and high surface quality; then, depositing a dielectric layer film with a certain micro-nano thickness on the substrate, and observing the thickness and the surface appearance of the dielectric layer film; determining an ion beam polishing process removal function of the dielectric layer film through a single-point resident polishing test; determining an equivalent raster scanning removal function and the height of the micro-nano step according to the single-point resident removal function, and performing regional processing on the dielectric layer film under the conditions of different scanning speeds by adopting a raster path scanning method; detecting the height, surface shape precision and surface roughness of the single micro-nano step by using a detection device, judging whether the detection result meets the machining precision requirement, and if not, re-adopting an ion beam polishing process to shape and machine the single micro-nano step; and finally, storing the micro-nano step processing information to a database.

As shown in fig. 2: and carrying out a dielectric layer film single-point resident polishing test on an ion beam polishing machine tool to obtain a removal function A (x, y). The experiment will develop a systematic study based on several ion beam process parameters: ion beam incident angle (θ), ion beam energy (E), ion beam dwell time (T)_e) And the distance (D) between the ion source and the target surface. In a coordinate system OXYZ, the distribution of the single-point resident pit array in the X direction and the Y direction is reasonably set according to the surface area of the substrate, and the distances between adjacent pits in the X direction and the Y direction are respectively delta X and delta Y. The thickness of the dielectric thin film is H, and the depth of the pit is d_iThat means that the distance of the bottom of the pit from the surface of the substrate is h_i＝H-d_i. The single-point resident pits on the surface of the dielectric layer film are processed by adopting different ion beam process parameters, so that pits with different depths are generated.

After the test, the profile of the single-point pit is detected by a profiler (PGI1240, TaylorHobson), and the detection result is subjected to straight line fitting, and the fitting result can reflect the stability of ion beam processing to a certain extent. Then, a Gaussian function is obtained by removing the contour fit of the center of the single-point pit, and the surface average removal rate (R) is estimated according to the Gaussian function_surf) And removing the size of the function full width at half maximum beam diameter (FWHM).

As shown in fig. 3: in order to realize large-area and high-efficiency polishing processing of a step-type micro-nano step array structure, an equivalent raster scanning removal function and micro-nano step height can be determined based on a processing result of an ion beam single-point residence polishing test; meanwhile, the process path and the scanning speed of the ion beam polishing process need to be planned. The ion beam process path adopts a raster path scanning mode, and the setting of the scanning step distance of the ion beam process path follows the following principle:

in the formula f_cTo remove the cut-off frequency of the function. The width of the Gaussian-like removal function is d_6σThen the cut-off frequency of the removal function can be expressed as:

and then, performing regional processing on the dielectric layer film material by adopting a raster path scanning method under the condition of different scanning speeds, namely, circularly moving the ion beam on the surface of the defined region in a raster scanning mode, and finally forming the micro-nano step array structures with different heights.

Taking the processing of the 3 × 3 micro-nano step array structure as an example, first, as shown in fig. 3 (a), the 3 × 1 micro-nano step array structure in the OX direction is processed, and the ion beam is in the region X₁Region X₂And region X₃Respectively at v, of the scanning feed speed_x1、v_x2And v_x3And the following relationship exists between them: v. of_x1<v_x2<v_x3And then, as shown in (b) of fig. 3, the 3 × 1 micro-nano step array structure in the OY direction is processed, and the ion beam is in the region Y₁Region Y₂And region Y₃Respectively at v, of the scanning feed speed_y1、v_y2And v_y3And the following relationship exists between them: v. of_y1>v_y2>v_y3Thus, a 3 × 1 micro-nano step array structure is formed in the OX direction, and the 3 × 1 micro-nano step array structures in the OX direction and the OY direction are mutually superposedFinally, a 3 × 3 micro-nano step array structure as shown in fig. 3 (c) is formed on the surface of the dielectric layer film.

Similarly, for processing the m × n micro-nano step array structure, firstly, the m × 1 micro-nano step array structure in the OX direction is processed, and the surface of the dielectric layer film is divided into areas X in the OX direction₁Region X₂… …, region X_mIon beam in region X₁Region X₂… …, region X_mCorresponding scan feed rates are v_x1、v_x2、……、v_xmAnd the following relationship exists between them: v. of_x1<v_x2<……<v_xmThen, processing the n × 1 micro-nano step array structure in the OY direction, and dividing the surface of the dielectric layer film into areas Y in the OY direction₁Region Y₂… …, region Y_nIon beam in region Y₁Region Y₂… …, region Y_nCorresponding scan feed rates are v_y1、v_y2、……、v_ynAnd the following relationship exists between them: v. of_y1>v_y2>……>v_ynAnd an n × 1 micro-nano step array structure is formed in the OY direction, the m × 1 in the OX direction and the n × 1 micro-nano step array structure in the OY direction are mutually superposed, and finally, an m × n micro-nano step array structure is formed on the surface of the dielectric layer film.

Then, with the processing result of the 3 × 3 micro-nano step array structure as a detection object, detecting the height, surface shape precision and surface roughness of a single micro-nano step by using detection devices such as a profiler (PGI1240, TaylorHobson), a laser interferometer (GPI (TM) XPD, Zygo) and an atomic force microscope (MultiMode8, Bruker), and the like, judging whether the detection result meets the processing precision requirements, namely the step height error is less than or equal to +/-5 nm, the surface shape precision PV is less than or equal to lambda/10, the surface roughness Ra is less than or equal to 1nm, if not, re-adopting an ion beam polishing process to shape the single micro-nano step according to the detection result, and finally storing the micro-nano step processing information into a database.

In the embodiment, a 3 × 3 micro-nano step array structure is taken as a processing object, and the specific test steps are as follows:

(1) a silicon wafer substrate with the size phi of 50.8 × 2mm or quartz glass with the size 55mm × 55mm × 2mm is used as a substrate material, and in order to ensure the reliability and stability of the high-precision manufacturing process of the micro-nano step array structure, certain requirements are required for the surface precision and the surface quality of a customized large-area substrate material, wherein the surface shape precision PV in the full aperture range is less than or equal to lambda/10, the surface roughness Ra is less than or equal to 1nm, and the defects such as cracks, scratches, pits and the like are not allowed to appear on the surface.

(2) The dielectric layer film material is selected from titanium dioxide (TiO)₂) Depositing a dielectric layer thin film material with the thickness in the optical thickness range (1000 nm) on the prepared substrate material by an electron beam evaporation system (KurtJ, L esker, L ab-L ine), wherein the vacuum pressure of the cavity is lower than 6 × 10 in the room temperature environment^-7Starting deposition at Torr and evaporating deposition rate ofThe deposition rate is required to be stable in the film deposition process, the film thickness is uniform, and no surface stress is released after deposition. After the dielectric layer thin film deposition is finished, measuring the thickness of the thin film by using a spectroscopic ellipsometer (SE-VE), and analyzing the deposition error of the measured data; the surface morphology of the obtained dielectric layer film was observed by a field emission scanning electron microscope (FESEM, zeiss sigma-HD).

(3) And carrying out a dielectric layer film single-point resident polishing test on an ion beam polishing machine tool to obtain a removal function A (x, y). The experiment will develop a systematic study based on several ion beam process parameters: ion beam incident angle (θ), ion beam energy (E), ion beam dwell time (T)_e) And the distance (D) between the ion source and the target surface. In a coordinate system OXYZ, the distribution of the single-point resident pit array in the X direction and the Y direction is reasonably set according to the surface area of the substrate, and the distances between adjacent pits in the X direction and the Y direction are respectively delta X and delta Y. The thickness of the dielectric thin film is H, and the depth of the pit is d_iIndicates, then pitThe bottom is at a distance h from the surface of the substrate_i＝H-d_i. The single-point resident pits on the surface of the dielectric layer film are processed by adopting different ion beam process parameters, so that pits with different depths are generated.

(4) After the test, the profile of the single-point pit is detected by a profiler (PGI1240, Taylor Hobson), and the detection result is subjected to straight line fitting, and the fitting result can reflect the stability of ion beam processing to a certain extent. Then, a Gaussian function is obtained by removing the contour fit of the center of the single-point pit, and the surface average removal rate (R) is estimated according to the Gaussian function_surf) And removing the size of the function full width at half maximum beam diameter (FWHM).

(5) In order to realize large-area and high-efficiency polishing processing of a step-type micro-nano step array structure, an equivalent raster scanning removal function and micro-nano step height can be determined based on a processing result of an ion beam single-point residence polishing test; meanwhile, the process path and the scanning speed of the ion beam polishing process need to be planned. The ion beam process path adopts a raster path scanning mode, and the setting of the scanning step distance of the ion beam process path follows the following principle:

in the formula f_cTo remove the cut-off frequency of the function. The width of the Gaussian-like removal function is d_6σThen the cut-off frequency of the removal function can be expressed as:

then, the dielectric layer film material is processed with different regions under different scanning speed conditions by adopting a raster path scanning method, namely, ion beams circularly move on the surface of the defined region in a raster scanning mode to finally form micro-nano step array structures with different heights, the detailed operation steps are as follows, firstly, as shown in (a) of figure 3, the 3 × 1 micro-nano step array structure in the OX direction is processed, and the ion beams are processed in the region X₁Region X₂And region X₃Respectively at v, of the scanning feed speed_x1、v_x2And v_x3And the following relationship exists between them: v. of_x1<v_x2<v_x3And then, as shown in (b) of fig. 3, the 3 × 1 micro-nano step array structure in the OY direction is processed, and the ion beam is in the region Y₁Region Y₂And region Y₃Respectively at v, of the scanning feed speed_y1、v_y2And v_y3And the following relationship exists between them: v. of_y1>v_y2>v_y3And a 3 × 1 micro-nano step array structure is formed in the OX direction, the 3 × 1 micro-nano step array structures in the OX direction and the OY direction are mutually superposed, and finally a 3 × 3 micro-nano step array structure shown in (c) of fig. 3 is formed on the surface of the dielectric layer film.

(6) The processing result of the 3 × 3 micro-nano step array structure is taken as a detection object, detection devices such as a contourgraph (PGI1240, Taylor Hobson), a laser interferometer (GPI (TM) XPD, Zygo) and an atomic force microscope (MultiMode8, Bruker) are adopted to detect the height, the surface shape precision and the surface roughness of a single micro-nano step, then, whether the detection result meets the processing precision requirement is judged, wherein the step height error is less than or equal to +/-5 nm, the surface shape precision PV is less than or equal to lambda/10, the surface roughness Ra is less than or equal to 1nm, and if the detection result does not meet the processing precision requirement, the ion beam polishing process is adopted again to carry out shape modification processing on the single micro-nano step according to the detection.

(7) And selecting proper shape modification process parameters, performing shape modification processing on the single micro-nano step with the detection result not meeting the requirement on an ion beam polishing machine, and detecting and evaluating the single micro-nano step by using related detection equipment after the shape modification processing is finished. And finally, storing the micro-nano step processing information to a database.