Preparation method of three-dimensional micro-nano origami structure

Abstract

The invention discloses a rapid and efficient preparation method of a three-dimensional micro-nano origami structure, which comprises the following steps: S1, processing a micro-nano thin film sample to obtain a patterned sample; s2, the patterned sample is bombarded through ions, the patterned sample is bent, the three-dimensional micro-nano origami structure is obtained, and the light spot area of the ions and the overall bombarded area of the patterned sample have a proportional relation. According to the method, the whole sample is bombarded through large beam spots of the ion beams in the first ion beam system, so that the whole sample structure is subjected to stress of the same degree, the bending effect of the whole structure is formed, and the large-area three-dimensional origami structure is rapidly prepared.

Description

Technical Field

[0001] This application relates to the field of processing of metasurface structural units, and specifically to a method for preparing a three-dimensional micro-nano origami structure. Background Art

[0002] With the continuous development of microelectronics technology, the application of three-dimensional curved structures has become increasingly widespread. Compared with two-dimensional micro-nano structures, three-dimensional structures have advantages such as higher controllable degrees of freedom and smaller volumes. For example, in the design of stealth metamaterials and negative refractive index metamaterials, three-dimensional structures are required for preparation. Moreover, three-dimensional metamaterials also play an important role in realizing superlenses or light enhancement devices through plasmon focusing. In addition, the characteristic size of plasmonic structures is proportional to the wavelength of light waves and has the characteristics of sub-wavelength. Therefore, progress in the preparation of three-dimensional micro-nano origami structures will have a huge impact on the application of three-dimensional metamaterials. In three-dimensional metamaterials, optical devices with curved or folded structures have more prominent light regulation capabilities than traditional three-dimensional structures. Therefore, the current device preparation direction mainly focuses on how to obtain three-dimensional micro-nano curved and folded structures. In addition, in the design of three-dimensional electrical devices, three-dimensional micro-nano origami structures can improve the performance and integration of electrical devices, and play an important role in the design of high-integration and high-efficiency devices.

[0003] The processing of general three-dimensional structures mainly relies on technologies such as laser direct writing and 3D printing. Although these technologies can process complex three-dimensional structures, they are greatly limited in the processing materials, generally only applicable to the processing of three-dimensional structures of polymers, and the processing efficiency is low. In order to prepare three-dimensional structures more flexibly, a three-dimensional origami processing technology has been proposed. This technology is compatible with two-dimensional planar processing processes and is flexible in preparation. Its processing idea mainly relies on the three-dimensional folding or bending of two-dimensional patterned structures, such as compressive buckling technology, residual stress-induced bending technology, etc. The former can prepare a two-dimensional pattern on a stretched flexible substrate, and the pattern is combined with the substrate through several connection points. When the substrate returns from the stretched state, the two-dimensional pattern will be compressed, resulting in buckling, and thus a complex three-dimensional structure is obtained. However, these technologies have disadvantages such as limited processing size, difficulty in controlling the bending shape, and slow processing speed. Therefore, new processing technologies are needed to quickly prepare large-area three-dimensional micro-nano origami structures. Summary of the Invention

[0004] In order to solve the above technical problems, this application is proposed. The embodiments of this application provide a method for preparing a large-area three-dimensional micro-nano origami structure more quickly, including:

[0005] The first step is to process a micro-nano scale thin film sample to obtain a patterned sample;

[0006] In the second step, the patterned sample is bombarded with an ion beam to bend the patterned sample, obtaining a three-dimensional micro / nano origami structure, wherein there is a proportional relationship between the spot area of the ion beam and the overall bombarded area of the patterned sample. As an example, for instance, the spot area of the ion beam is directly proportional to the overall bombarded area of the patterned sample.

[0007] In one embodiment, before the first step, the preparation method further includes: preparing a second thin film material on a first thin film material as the sample, wherein the sample is suspended at at least one edge. In a preferred embodiment, the sample is suspended at three of its edges.

[0008] In one embodiment, the second step includes: placing the patterned sample in the cavity of a first ion beam system, and bombarding the entire patterned sample with the ion beam emitted by the first ion beam system, so that the overall structure of the patterned sample bends.

[0009] In one embodiment, bombarding the entire patterned sample with the ion beam emitted by the first ion beam system, so that the overall structure of the patterned sample bends includes: bombarding the entire patterned sample with the ion beam emitted by the first ion beam system, so that the entire patterned sample is subjected to the same degree of stress, forming an overall structure bend.

[0010] In one embodiment, preparing a second thin film material on a first thin film material as the sample includes: the first thin film material is a dielectric thin film or a metal thin film obtained by a transfer method; wherein, the dielectric thin film includes one or more combinations of a silicon nitride thin film window, a silicon dioxide thin film window, and a silicon thin film window; the metal thin film includes a metal that can be evaporated by an electron beam metal coating system; wherein, the thickness ranges of the dielectric thin film and the metal thin film are 20 nanometers to 100 nanometers.

[0011] In one embodiment, the second thin film material is a single-layer thin film material composed of any one of a metal material, a dielectric material, and a semiconductor material.

[0012] In one embodiment, the thickness of the second thin film material is less than half of the thickness of the first thin film material.

[0013] In one embodiment, the first step is to process the sample using a focused ion beam system (FIB), wherein the ion voltage of the focused ion beam system is fixed at 30 KV, the ion beam current is at least greater than 33 pA, and the etching depth of the patterned sample is at least greater than 10 nm; and / or in the second step, the voltage of the ion beam is fixed at 300 V, and the etching time is greater than or equal to 30 s, so that the structure of the patterned sample deforms.

[0014] In one embodiment, the bending angle of the patterned sample is controlled by adjusting the pattern size of the sample, the etching time of the ion beam, or the energy of the ion beam.

[0015] In one embodiment, before preparing the second thin film material as the sample on the first thin film material, the preparation method further includes preparing the first thin film material based on support of a substrate.

[0016] The preparation method of the three-dimensional micro-nano origami structure provided by the present invention has a processing mechanism that uses the nanoscale precision, extremely small beam spot, and beam current of the gallium ion beam in the first ion beam system to cut the thin film material to generate a pattern, introducing stress as small as possible. A larger ion beam current will cause the thin film to bend or fold during the initial processing. Then, the entire sample is bombarded by the argon ion beam in the first ion beam system with a large beam spot to generate stress, thereby realizing the bending of the thin film, and the bending angle of the three-dimensional structure can be controlled by adjusting the etching time and energy. The preparation process is simple and faster than before.

[0017] Each time the thin film is cut using a focused ion beam system, the test dose (here, the etching depth is changed), and an interval dose (10 nm, 20 nm, 30 nm) is set to find a dose that can completely cut through the thin film without warping due to the ion beam irradiation of the focused ion beam system. Because if the cutting dose of the focused ion beam system is too large, it will directly cause bending and cannot accurately control the bending angle, which will cause trouble for subsequent processing.

[0018] Moreover, lithography technology can be combined to prepare more complex two-dimensional patterns and ion beam cutting to achieve precise control of three-dimensional micro-nano origami, greatly improving the processing speed and flexibility of small-size, large-area micro-nano structures.

[0019] The preparation method of the three-dimensional micro-nano origami structure provided by the present invention has the following technical advantages:

[0020] 1) By jointly controlling the configuration of the three-dimensional structure through the design of a predetermined pattern and the ion beam cutting process, this method can achieve a more precise and controllable three-dimensional configuration, greatly improving the richness of the structure and increasing the designability of the structure.

[0021] 2) The process adopted in the present invention is simpler, more efficient, lower in cost and has better universality for materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and other objects, features and advantages of the present application will become more apparent by describing the embodiments of the present application in more detail in conjunction with the accompanying drawings. The accompanying drawings are used to provide a further understanding of the embodiments of the present application, and constitute a part of the specification, and are used to explain the present application together with the embodiments of the present application, and do not constitute a limitation to the present application. In the drawings, the same reference numerals generally represent the same components or steps.

[0023] Figure 1 It is a schematic flowchart of a method for preparing a three-dimensional micro-nano origami structure according to an embodiment of the present invention.

[0024] Figure 2 It is a schematic diagram of the preparation process of a method for preparing a three-dimensional micro-nano origami structure according to an embodiment of the present invention.

[0025] Figure 3 It is a schematic diagram of a patterned array structure according to Embodiment 1 of the present invention.

[0026] Figure 4 It is a schematic diagram of a patterned array structure according to a variant of Embodiment 1 of the present invention.

[0027] Figure 5 It is an experimental diagram of ion beam etching processing according to Embodiment 1 of the present invention.

[0028] Figure 6 It is a schematic diagram of a bending structure according to Embodiment 1 of the present invention.

[0029] Figure 7 It is a measurement diagram of the bending angle according to Embodiment 1 of the present invention.

[0030] Figure 8 It is a schematic diagram of a bending structure according to a variant of Embodiment 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] Hereinafter, exemplary embodiments of the present application will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. It should be understood that the present application is not limited by the exemplary embodiments described herein.

[0032] Figure 1Shows a schematic flow chart of a method for preparing a three-dimensional micro-nano origami structure according to an embodiment of the present invention. Figure 2 Shows a schematic diagram of the specific preparation process of a three-dimensional micro-nano origami structure according to an embodiment of the present invention. By bombarding the surface of the thin film material with an ion beam, stress is caused to make it bend, and the bending angle of the two-dimensional thin film is controlled by controlling the etching time, combined with Figure 1 and Figure 2 It can be known that the method provided according to an embodiment of the present invention may include the following steps:

[0033] Step S1: Support based on a preset substrate a to prepare a suspended first thin film material b, and prepare a second thin film material d on the first thin film material b through a deposition technique c for use as a sample.

[0034] Among them, the first thin film material b can be a metal thin film, a dielectric thin film, a two-dimensional material, etc. obtained by a transfer method. The dielectric thin film can be one of a commercially purchased silicon nitride thin film window, a silicon dioxide thin film window, or a silicon thin film window. When preparing the first thin film material b, a silicon nitride thin film window, a silicon dioxide thin film window, or a porous silicon thin film window, etc. can be obtained through wet etching or etching processes. The thickness of the first thin film material b can be between 10 nanometers and 100 nanometers.

[0035] Optionally, when preparing the second thin film material d on the first thin film material b, it can be prepared by a physical deposition method such as electron beam evaporation deposition or a chemical deposition technique such as chemical vapor deposition. The second thin film material d can be a single-layer thin film material composed of any one of a metal material, a dielectric material, or a semiconductor material; or the second thin film material d can be a multi-layer thin film material composed of a metal material, a dielectric material, and a semiconductor material.

[0036] Step S2: Place the sample in a focused ion beam system for etching e, use a gallium ion source to cut the pattern of the sample, and form at least one suspended patterned sample with a first predetermined pattern on the surface of the sample.

[0037] The suspended patterned sample can be obtained by etching with a gallium ion source in a focused ion beam system; it can also be obtained by spin-coating a photoresist on the second thin film material, and then obtaining the first predetermined pattern through techniques such as electron beam exposure, ultraviolet exposure, or laser direct writing, and then performing etching e. Etching e can use a dry etching technique or a physical and chemical etching, such as ion milling etching, reactive ion etching, or inductively coupled etching, etc.

[0038] The type of the pattern can be more than one, and the present invention does not limit the quantity and size.

[0039] Step S3: Place the obtained suspended patterned sample with the first predetermined pattern in an ion beam etching system, and bombard it with an argon ion source to obtain a bent structure f.

[0040] The bent structure can be the bending of a single-layer film, the bending of a multi-layer film, or the bending of many different shapes and sizes. The bending angle of the bent structure f can be any angle from 0 to 90°. Bombarding the suspended patterned sample with ions emitted by the ion source in the ion beam etching system can bend the sample over a large area to obtain the bent structure f. When bombarding, the bending angle can be adjusted by adjusting the etching time or changing the energy of the argon ion source.

[0041] The shape, size, and area of the three-dimensional micro-nano origami structure prepared by the preparation method provided in the embodiment of the present invention can all be freely adjusted. Specifically, the shape, size, and area of the three-dimensional micro-nano origami structure can be adjusted by changing the thickness of the suspended film, the size of the pattern, the ion dose emitted by the ion source of the ion beam etching system, and the etching time. For example, different patterns will produce different bending angles under the bombardment of the same argon ion source energy and time, but still maintain good consistency. Optionally, the ion beam parameters include: gallium ion beam energy, dose, beam current, and argon ion source energy and etching time.

[0042] By testing to count the bending degree of structures of different sizes at the same time. When the front focused ion beam system cuts, different sizes, deformations, and areas of structures are made by designing the layout. In a four-inch area, for samples cut out in the same batch, after being etched by the ion beam etching system, the consistency of their bending angles reaches more than 95% (when measuring the angles under a scanning tunneling microscope, it is found that the error is small).

[0043] The following will be described in detail with specific embodiments.

[0044] Example 1

[0045] Step S1-1: Prepare a 50-nm-thick silicon nitride window in advance, place it in a reactive ion etching system, and perform oxygen plasma cleaning for 15 seconds. After cleaning, paste the silicon nitride window on a carrier wafer, and deposit a 20-nm-thick gold film using an electron beam evaporation system.

[0046] Step S1-2: Place the sample obtained in Step S1-1 in the chamber of the focused ion beam system.

[0047] Among them, set the ion source voltage of the focused ion beam system to 30 KV, the ion beam current to 83 pA, and the etching depth to 40 nm. Use the method of ion beam wire cutting to cut along the predetermined pattern to obtain a thin film pattern with three sides suspended. Figure 3Schematic diagrams of the patterned array structures of Example 1 and one of its variants are shown. As Figure 3 shown, the sizes of the displayed patterns are 6x4um and 4x4um respectively.

[0048] Steps S1-3: Paste the sample obtained in Step S1-2 onto a four-inch silicon wafer. As Figure 5 shown, place it in the cavity of an ion beam etching system, set the ion voltage to 300V, and the etching time to 150s. By using the method of bombarding with argon ions, a three-dimensional micro-nano origami structure with a curved structure can be obtained. As Figure 6 shown.

[0049] Re-place the three-dimensional micro-nano origami structure obtained in Step S1-3 into the focused ion beam system, and use the measurement function of this device to measure and calculate the consistency of the origami structure. As Figure 7 shown.

[0050] In the above embodiment, the suspended thin film material in Step S1-1 can be selected as other materials according to the actual situation, not limited to the dielectric thin film involved in the embodiment. The patterns in Step S1-2 can be designed according to requirements, not limited to the patterns mentioned in the embodiment. Figure 4 and Figure 8 respectively show the schematic diagram of the patterned array structure of one variant of Example 1 and the schematic diagram of its curved structure.

[0051] The biggest feature different from the past in the preparation method of the three-dimensional micro-nano origami structure provided in the embodiments of the present invention is the preparation of the curved structure. In the prior art, by ion beam irradiation, non-uniformly distributed tensile stress is introduced into a single structure in a suspended material, so that the thin film will bend or fold in the three-dimensional direction under its action. In the present invention, by bombarding with an ion source, the entire sample structure is subjected to the same degree of stress, thereby forming a bending effect of the overall structure. This breaks through the disadvantage that the ion source irradiation of the focused ion beam system in the previous processing method can only process single structures one by one, thus realizing the rapid preparation of large-area three-dimensional origami structures.

[0052] The preparation method of the three-dimensional micro-nano origami structure provided in the embodiments of the present invention has the advantages of simple process, high efficiency, low cost and universality for materials. The prepared structures are rich in variety and the characteristic dimensions are precisely controllable.

[0053] The basic principles of the present application have been described above in connection with specific embodiments. However, it should be noted that the advantages, benefits, effects, etc. mentioned in the present application are merely examples and not limitations, and it cannot be considered that these advantages, benefits, effects, etc. are essential for each embodiment of the present application. In addition, the above-disclosed specific details are only for illustrative and facilitating understanding purposes, rather than limitations. The above details do not limit the present application to necessarily adopt the above specific details for implementation.

[0054] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0055] The above description has been given for purposes of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A method for preparing a three-dimensional micro-nano origami structure, comprising: The first step of processing a micro-nano scale thin film sample to obtain a patterned sample; The second step of bombarding the patterned sample with an ion beam to bend the patterned sample to obtain a three-dimensional micro-nano origami structure, wherein there is a proportional relationship between the beam spot area of the ion beam and the overall bombarded area of the patterned sample.

2. The preparation method according to claim 1, wherein, Before the step 1, the preparation method further includes: preparing a second thin film material on a first thin film material as the sample, wherein the sample is suspended at at least one edge.

3. The preparation method according to claim 1, wherein The second step includes: Placing the patterned sample in the cavity of a first ion beam system, and bombarding the entire patterned sample with the ion beam emitted by the first ion beam system, so that the overall structure of the patterned sample bends.

4. The preparation method according to claim 3, wherein, The bombarding the entire patterned sample with the ion beam emitted by the first ion beam system, so that the overall structure of the patterned sample bends includes: Bombarding the entire patterned sample with the ion beam emitted by the first ion beam system, so that the entire patterned sample is subjected to the same degree of stress to form an overall structure bend.

5. The preparation method according to claim 2, wherein, Preparing a second thin film material on a first thin film material as the sample includes: The first thin film material is a dielectric thin film or a metal thin film obtained by a transfer method; Wherein, the dielectric thin film includes one or more combinations of a silicon nitride thin film window, a silicon dioxide thin film window, and a silicon thin film window; the metal thin film includes a metal that can be evaporated by an electron beam metal coating system; Wherein, the thickness range of the dielectric thin film and the metal thin film is 20 nanometers to 100 nanometers.

6. The preparation method according to claim 2, wherein, The second thin film material is a single-layer thin film material composed of any one of a metal material, a dielectric material, and a semiconductor material.

7. The preparation method according to claim 6, wherein The thickness of the second thin film material is less than half of the thickness of the first thin film material.

8. The preparation method according to claim 1, wherein The first step is to process the sample using a focused ion beam system, wherein the ion voltage of the focused ion beam system is fixed at 30 KV, the ion beam current is at least greater than 33 pA, and the etching depth of the patterned sample is at least greater than 10 nm; and / or In the second step, the voltage of the ion beam is fixed at 300 V, and the etching time is greater than or equal to 30 s, so that the structure of the patterned sample deforms.

9. The preparation method according to claim 1, wherein, The bending angle of the patterned sample is controlled by adjusting the pattern size of the sample, the etching time of the ion beam, or the energy of the ion beam.

10. The preparation method according to claim 2, wherein, Before preparing a second thin film material on a first thin film material as the sample, the preparation method further includes preparing the first thin film material based on a substrate for support.

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