CN113023667A

CN113023667A - Three-dimensional micro-nano bending structure and method for preparing same by using electron beam

Info

Publication number: CN113023667A
Application number: CN202110238211.9A
Authority: CN
Inventors: 顾长志; 郑睿瑄; 潘如豪; 杨海方; 金爱子; 李俊杰
Original assignee: Institute of Physics of CAS
Current assignee: Institute of Physics of CAS
Priority date: 2021-03-04
Filing date: 2021-03-04
Publication date: 2021-06-25
Anticipated expiration: 2041-03-04
Also published as: CN113023667B

Abstract

The invention relates to a three-dimensional micro-nano bending structure and a method for preparing the same by using electron beams. According to an exemplary embodiment, a method of manufacturing a three-dimensional bending structure may include: preparing a laminated structure including at least a first layer and a second layer on the first layer, the laminated structure having a body portion supported on a substrate and at least one overhanging pattern portion extending from the body portion; irradiating the overhanging pattern portion with an electron beam to bend the overhanging pattern portion, thereby obtaining a three-dimensional bent structure.

Description

Three-dimensional micro-nano bending structure and method for preparing same by using electron beam

Technical Field

The present invention generally relates to the field of micro-machining, and more particularly, to a three-dimensional micro-nano bending structure and a method for preparing the same using electron beams.

Background

With the continuous development of microelectronic technology, the application of three-dimensional structures is gradually widespread. Compared with a two-dimensional micro-nano structure, the three-dimensional structure has the advantages of higher controllable degree of freedom, smaller size and the like. For example, in the design of stealth metamaterials and negative refractive index metamaterials, three-dimensional structures are required to be fabricated. The three-dimensional metamaterial also plays an important role in realizing a superlens or a light enhancement device through plasmon focusing. In addition, the characteristic size of the plasmon structure is in direct proportion to the wavelength of the light wave, and the plasmon structure has the characteristic of sub-wavelength, so that the progress in the preparation of the three-dimensional micro-nano structure can generate great promotion effect on the application of the three-dimensional metamaterial. In the three-dimensional metamaterial, an optical device with a bent or curled structure has more outstanding light modulation and control capability than a traditional three-dimensional structure; in addition, in the design of the three-dimensional electrical device, the three-dimensional micro-nano bending structure can improve the performance and the integration level of the electrical device, and plays an important role in designing a device with high integration level and high efficiency. Therefore, how to obtain the three-dimensional micro-nano bending structure is an important problem in the preparation of the current device.

Originally, the processing of three-dimensional structures mainly relied on techniques such as laser direct writing and 3D printing, and although these techniques can process complex three-dimensional structures, the processing materials thereof are greatly limited, and generally only suitable for processing polymer three-dimensional structures, and the processing efficiency thereof is low. In order to more flexibly prepare the three-dimensional structure, a so-called three-dimensional paper folding processing technology is provided, and the technology has the characteristics of compatibility with a plane processing technology, flexibility in preparation and the like. The processing idea of the three-dimensional paper folding method is mainly realized by three-dimensional folding or curling of a two-dimensional graphical structure. For example, a two-dimensional pattern can be produced on a stretched flexible substrate, which pattern is bonded to the substrate by means of several connecting points. When the substrate is restored from the stretched state, the two-dimensional pattern is compressed, thereby causing buckling, thereby obtaining a complicated three-dimensional structure. However, this method has problems that it is difficult to control the bent shape, bending exceeding 180 ° cannot be generated, and the bent structure is restored to some extent after the substrate is removed.

Therefore, there is still a need for an improved method capable of conveniently and flexibly preparing a three-dimensional micro-nano bending structure of a desired shape.

Disclosure of Invention

The present invention has been made keeping in mind the above and other technical problems occurring in the art.

According to an aspect of the present invention, there is provided a method of fabricating a three-dimensional bent structure using an electron beam, including: preparing a laminated structure including at least a first layer and a second layer on the first layer, the laminated structure having a body portion supported on a substrate and at least one overhanging pattern portion extending from the body portion; irradiating the overhanging pattern portion with an electron beam to bend the overhanging pattern portion, thereby obtaining a three-dimensional bent structure.

In some embodiments, the first layer is formed of a dielectric material and the second layer is formed of a metallic material.

In some embodiments, preparing the laminate structure comprises: forming the first layer on the substrate; etching the first layer to form a body portion and an overhanging pattern portion extending from the body portion; forming a sacrificial layer pattern on the substrate, the sacrificial layer pattern exposing a body portion and an overhang pattern portion of the first layer; depositing a second layer on the sacrificial layer pattern and the body portion and the overhanging pattern portion of the first layer; removing the sacrificial layer pattern and a portion of the second layer deposited on the sacrificial layer pattern to obtain the stacked structure; and removing a portion of the substrate located under an overhanging pattern portion of the stacked structure, such that the main body portion is supported on the substrate and the overhanging pattern portion overhangs from the main body portion.

In some embodiments, preparing the laminate structure comprises: forming a first layer and a second layer on the first layer on the substrate; etching the first layer and the second layer to form a stacked structure including a body portion and an overhanging pattern portion extending from the body portion; and removing a portion of the substrate located under an overhanging pattern portion of the stacked structure, such that the main body portion is supported on the substrate and the overhanging pattern portion overhangs from the main body portion.

In some embodiments, preparing the laminate structure comprises: transferring a first layer onto the substrate, the substrate having at least one open area, the first layer covering the open area of the substrate; etching the first layer to form a body portion supported by the substrate and at least one overhanging pattern portion extending from the body portion into an open region of the substrate; and depositing the second layer on the first layer.

In some embodiments, preparing the laminate structure comprises: transferring a multilayer film comprising at least a first layer and a second layer on the first layer onto the substrate, the substrate having at least one open area, the multilayer film covering the open area of the substrate; and etching the multilayer film to form a body portion supported by the substrate and at least one overhanging pattern portion extending from the body portion into an opening area of the substrate.

In some embodiments, irradiating the overhanging pattern portion with an electron beam comprises: globally or locally irradiating an overhanging pattern portion of the second layer with an electron beam.

In some embodiments, globally or locally irradiating the overhanging pattern portion of the second layer with an electron beam comprises: scanning all or a partial area of the overhanging pattern portion of the second layer point by point with an electron beam.

According to another aspect of the present invention, there is provided a three-dimensional bent structure prepared by the above method, having a laminated structure including at least a first layer and a second layer on the first layer, the laminated structure including a body portion and at least one three-dimensional bent portion extending from the body portion.

In some embodiments, the thickness of each of the first layer and the second layer is in the range of 1nm to 100 μm, preferably in the range of 1nm to 1 μm, more preferably in the range of 1nm to 100 nm.

The above and other features and advantages of the present invention will become apparent from the following description of exemplary embodiments, which is to be read in connection with the accompanying drawings.

Drawings

Fig. 1 is a flowchart of a method for manufacturing a three-dimensional micro-nano bending structure according to an exemplary embodiment of the invention.

Fig. 2A-2D are schematic diagrams of steps for fabricating a stacked structure according to an exemplary embodiment of the present invention.

Fig. 3A-3C are schematic diagrams of steps for fabricating a stacked structure according to another exemplary embodiment of the present invention.

Fig. 4A-4D are schematic diagrams of steps for fabricating a stacked structure according to another exemplary embodiment of the present invention.

Fig. 5A-5C are schematic diagrams of steps for preparing a stacked structure according to another exemplary embodiment of the present invention.

Fig. 6 to 8 are schematic views of steps of irradiating an overhanging pattern portion with an electron beam according to some exemplary embodiments of the present invention.

Fig. 9 and 10 are photographs of three-dimensional micro-nano bent structures prepared according to some exemplary embodiments of the present invention.

Detailed Description

Hereinafter, example embodiments according to the present application will be described in detail with reference to the accompanying drawings. Note that the drawings may not be to scale. It should be apparent that the described embodiments are merely some embodiments of the present application and not all embodiments of the present application, which are not limited to the example embodiments described herein.

Fig. 1 is a flowchart of a method 100 for manufacturing a three-dimensional micro-nano bending structure according to an exemplary embodiment of the present invention. Here, "bent" means various non-flat structures such as bent, curled, folded, wrinkled, etc.; by "micro-nano" it is meant that the dimensions of the structure, e.g. the thickness, may be in the order of micro and nano, e.g. in the range from 1nm to 100 μm. Of course, it should be understood that the principles of the present invention are not limited to the bend shapes or sizes given herein as examples, but may also be applied to other various bend shapes and sizes.

Referring to fig. 1, a method 100 of fabricating a three-dimensional micro-nano bending structure may include a step S110 of fabricating a stacked structure including at least a first layer and a second layer on the first layer, the first layer may be formed of a dielectric material, and the second layer may be formed of a metal material. The laminated structure has a body portion supported on a substrate, and at least one overhanging pattern portion extending from the body portion, or may also be referred to as a cantilever structure. Some exemplary embodiments of step S110 of preparing a stacked structure will be described below with reference to fig. 2A-5C.

Fig. 2A-2D are schematic diagrams of steps for fabricating a stacked structure according to an exemplary embodiment of the present invention. Referring first to fig. 2A, a first layer 220 is formed on a substrate 210. The first layer 220 may be made of a dielectric material such as silicon dioxide (SiO)₂) Alumina (Al)₂O₃) Silicon nitride (SiN), etc., and the thickness thereof may be in the range of 1nm to 100 μm, preferably in the range of 1nm to 1 μm, more preferably in the range of 1nm to 100 nm. For example, the thickness of the first dielectric layer 220 may be tens of nanometers. The first layer 220 may be formed on the substrate 210 by various methods. For example, first layer 220, which is commercially purchased or deposited on another substrate, can be transferred to substrate 210, or first layer 220 can be deposited directly on substrate 210, examples of deposition methods including, but not limited to, atomic layer deposition, thermal evaporation deposition, electron beam deposition, magnetron sputtering deposition, plasma pulse deposition, chemical vapor deposition, plasma enhanced chemical vapor deposition, and the like.

Referring to fig. 2B, a photoresist (also referred to as a photoresist) pattern 230 is formed on the first layer 220, and the first layer 220 is etched using the photoresist pattern 230 to form a main portion of the first layer 220 and an overhang pattern portion extending from the main portion, which will be described further later. Examples of the photoresist that can be used in this step include, but are not limited to, electron beam resists such as positive resist PMMA (polymethyl methacrylate) and negative resist HSQ, ultraviolet resists such as positive resist AZ and negative resist SU8, and the like, or resists suitable for other exposure methods. Depending on the type of photoresist selected, the exposure method used to form the photoresist pattern 230 may be an optical exposure technique such as violet exposure, deep ultraviolet exposure, laser direct write exposure, or an electronic exposure technique such as electron beam exposure, and may employ a single exposure or multiple overlay exposures. In some embodiments, the resulting photoresist pattern 230 has a desired pattern shape, i.e., has a main portion and one or more overhanging pattern portions extending from the main portion. It is understood that a plurality of photoresist patterns 230 may be formed on the first layer 220 in a repeated arrangement, and the present invention is not limited thereto. In etching the first layer 220 using the photoresist pattern 230, a dry etching technique or a wet etching technique may be employed. For example, the dry etching technique may include ion milling etching, reactive ion etching, inductively coupled plasma reactive ion etching, and the like, and the wet etching may be performed by using a chemical etching means such as hydrofluoric acid, potassium hydroxide, and the like. It is to be understood that an appropriate etching method may be selected according to the formation material of the first layer 220. After the etching is completed, the photoresist layer 230 may be removed.

With continued reference to fig. 2C, a sacrificial layer pattern 240 is formed on the substrate 210, covering the substrate 210 but exposing a body portion and an overhanging pattern portion of the first layer 220. In some embodiments, the sacrificial layer pattern 240 may also be formed by an exposure development process using a photoresist material, and the thickness of the sacrificial layer pattern 240 may be significantly greater than that of the first layer 220, for example, a thickness of several hundreds of nanometers to several micrometers. Then, a second layer 250 may be deposited on the sacrificial layer pattern 240 and the exposed first layer 220. The second layer 250 may be formed of a metal material, the metal material may include a simple metal or an alloy, examples of which include, but are not limited to, gold, silver, aluminum, copper, iron, etc., and the second layer 250 may include a single layer or a composite multi-layer structure formed of different materials. The thickness of the second layer 250 may be in the range of 1nm to 100 μm, preferably in the range of 1nm to 1 μm, more preferably in the range of 1nm to 100 nm. For example, the thickness of the second layer 250 may be tens of nanometers, and the thickness of the second layer 250 may be greater than, less than, or equal to the thickness of the first layer 220, as desired. In the step shown in fig. 2C, the second layer 250 may be formed by various deposition processes, examples of which include, but are not limited to, physical deposition methods such as magnetron sputtering, electron beam evaporation deposition, thermal evaporation, or chemical deposition methods such as chemical vapor deposition methods. Preferably, the second layer 250 may be formed through a directional deposition process such that it does not completely cover at least sidewalls of the sacrificial layer pattern 240. The thickness of the sacrificial layer pattern 240 may be significantly or substantially greater than the total thickness of the first and

second layers

220 and 250 such that a portion of the sidewalls of the sacrificial layer pattern 240 is exposed. After depositing the second layer 250, the sacrificial layer pattern 240 and the portion of the second layer 250 located thereon may be removed, resulting in a stacked structure including the first layer 220 and the second layer 250, and including a desired shape composed of a body portion and an overhanging pattern portion extending from the body portion.

Referring now to fig. 2D, the portion of substrate 210 underlying overhanging pattern portion 206 of stacked structure 202 is removed such that body portion 204 of stacked structure 202 is supported on the substrate while overhanging pattern portion 206 of stacked structure 202 overhangs body portion 204. The method of etching the substrate 210 may be selected according to the materials of the substrate 210, the first layer 220, and the second layer 250. For example, when the substrate 210 is a silicon substrate, the first layer 220 is an aluminum oxide layer, and the second layer 250 is a metal layer, sulfur hexafluoride and oxygen plasma may be used to etch the substrate 210. Of course, depending on the materials of these layers, an appropriate etchant may be selected to wet etch the substrate 210. It will be appreciated that the step of etching the substrate 210 here is isotropic etching, such that the portion of the substrate below the overhanging pattern portion 206 is etched away, whereas by setting the two-dimensional planar dimensions of the body portion 204 such that the portion of the substrate below it is only peripherally etched, the body portion 204 can still be supported on a portion of the substrate 210, as shown in fig. 2D. In some embodiments, the substrate portions removed by the step shown in fig. 2D may be sacrificial material pre-formed in substrate 210, such that these substrate portions may be more easily removed while body portion 204 remains supported on the remaining substrate portions. As shown in fig. 2D, in the resulting laminated structure 202, one end of the overhang pattern portion 206 is fixedly connected to the body portion 204, and the other end is a free end that overhangs, i.e., is not fixedly connected to the substrate 210.

Fig. 3A-3C are schematic diagrams of steps for fabricating a stacked structure according to another exemplary embodiment of the present invention. In fig. 3A-3C, structures that are the same as in fig. 2A-2D are denoted with the same reference numerals, and are only briefly described below to avoid redundancy, some specific details may be found in the above-described embodiments.

Referring to fig. 3A, a first layer 220 and a second layer 250 on the first layer 220 are formed on a substrate 210. Either or both of the first layer 220 and the second layer 250 may be commercially purchased or transferred to the substrate 210 after deposition on another substrate, or deposited directly on the substrate 210.

Referring to fig. 3B, a photoresist pattern 230 is formed on the multi-layer film structure of the first and

second layers

220 and 250, and the first and

second layers

220 and 250 are etched to form a stacked structure including a body portion and an overhanging pattern portion extending from the body portion. It is understood that the shapes of the body portion and the overhang pattern portion are defined by the photoresist pattern 230. After the etching is completed, the photoresist pattern 230 may be removed.

With continued reference to fig. 3C, the portion of substrate 210 underlying overhanging pattern portion 206 of stack-up structure 202 is removed such that body portion 204 of stack-up structure 202 is supported on the substrate while overhanging pattern portion 206 of stack-up structure 202 overhangs body portion 204. Thus, in the resulting laminated structure 202, one end of the overhanging pattern portion 206 is fixedly connected to the body portion 204, and the other end is an overhanging free end, i.e., is not fixedly connected to the substrate 210.

By successively forming the first layer 220 and the second layer 250 and etching the first layer 220 and the second layer 250 in the same step in the method of fig. 3A-3C, the process steps are reduced, making the process of forming the stacked-layer structure 202 simpler than the method shown in fig. 2A-2D. However, the method shown in fig. 2A-2D is preferred from the viewpoint of forming the meander structure later, because the stress in the first layer 220 can be partially released when the first layer 220 is etched separately and the second layer 250 is deposited on the first layer 220 after the etching is completed. Thus, when forming a bent structure later by electron beam induced stress, the stack 202 formed by the method shown in fig. 2A-2D can easily produce a large angle bend due to the stress difference in the first layer 220 and the second layer 250. In the method shown in fig. 3A-3C, since the first layer 220 and the second layer 250 are simultaneously deposited and etched, the stress difference therebetween may be relatively small, and thus it may be difficult to generate a large-angle bent shape. It will be appreciated that the method shown in figures 2A-2D is preferred when it is desired to produce a bend shape with a large angle bend, for example greater than 90 degrees, greater than 180 degrees or even greater than 360 degrees; while the approach shown in fig. 3A3C may be preferred for simplicity when only a small angle bend, e.g., less than 90 degrees, of bend shape is desired.

Fig. 4A-4D are schematic diagrams of steps for fabricating a stacked structure according to another exemplary embodiment of the present invention. In fig. 4A-4D, structures that are the same as in fig. 2A-2D and fig. 3A-3C are denoted with the same reference numerals, and are only briefly described below to avoid redundancy, and some specific details may be found in the above-described embodiments.

Referring to fig. 4A, a first layer 220 is formed on a substrate 210. In this embodiment, the first layer 210 is provided with open regions 211, which may be through-hole regions as shown in fig. 4A, or regions such as blind holes and recesses. In the step shown in fig. 4A, a first layer 220, which is commercially purchased or deposited on another substrate, may be transferred onto the substrate 210 and the first layer 220 is allowed to cover the open areas 211 of the substrate 210.

Referring to fig. 4B, a photoresist pattern 230 is formed on the first layer 220, and the first layer 220 is etched using the photoresist pattern 230 to form a main portion of the first layer 220 and an overhanging pattern portion extending from the main portion. In fig. 4B, the main body portion is a portion supported on the substrate 210, and the overhanging pattern portion is a portion overhanging from the main body portion into the opening region 211. It is understood that the step of forming the photoresist pattern 230 may include spin-coating a liquid photoresist on the first layer 220 shown in fig. 4A, solidifying it by heating, and then removing a portion of the photoresist by an exposure and development process to obtain a desired pattern. Since the solid photoresist has a certain strength, the overhanging pattern portion can still maintain its shape.

Then, referring to fig. 4C, the photoresist pattern 230 may be removed, and a second layer 250 is deposited on the first layer 220. In this step, since the periphery of the overhanging pattern portion of the first layer 220 is hollowed out, the second layer 250 is deposited on the overhanging pattern portion of the first layer 220 in self-alignment, forming an overhanging pattern portion having a stacked structure. It will be appreciated that because the first layer 220 has some strength, the overhanging pattern portion may have some sagging from its own weight and from the weight of the second layer 250 during this step, but still substantially retain its shape. In addition, the second layer 250 is also deposited onto the bulk portion of the first layer 210 and the exposed portions of the substrate 210. If desired, a dicing step may be performed later to separate the bulk portion of the laminate structure from the second layer 250 deposited directly on the substrate 210.

Fig. 4D shows the resulting structure after deposition of the second layer 250, wherein the body portion 204 of the stacked structure 202 is supported on the substrate 210, while the overhanging pattern portion 206 of the stacked structure 202 overhangs the body portion 204.

Fig. 5A-5C are schematic diagrams of steps for preparing a stacked structure according to another exemplary embodiment of the present invention. In fig. 5A-5C, structures that are the same as in fig. 2A-2D, 3A-3C, 4A-4D are identified with the same reference numerals, and are only briefly described below to avoid redundancy, some of which may be referred to in the above-described embodiments.

Referring to fig. 5A, a first layer 220 and a second layer 250 on the first layer 220 are formed on a substrate 210. The first layer 220 and the second layer 250 may be commercially purchased or previously deposited substrates on other substrates that are transferred to the substrate 210, and the multilayer film structure of the first layer 220 and the second layer 250 covers the open areas 211 of the substrate 210, while the solid portions of the substrate 210 may provide good support for the first layer 220 and the second layer 250.

Referring to fig. 5B, a photoresist pattern 230 is formed on the multi-layer film structure of the first and

second layers

220 and 250, and the first and

second layers

220 and 250 are etched to form a stacked structure including a body portion and an overhanging pattern portion extending from the body portion. It will be appreciated that the shape of the body portion, which is supported on a solid portion of the substrate 210, and the overhang pattern portion, which extends from the body portion into the open region 211 of the substrate 210, are defined by the photoresist pattern 230.

After the etching is completed, the photoresist pattern 230 may be removed, and fig. 5C shows the stack structure 202 obtained after the photoresist pattern 230 is removed, which includes the body portion 204 and the overhanging pattern portion 206. The body portion 204 is supported on a solid portion of the substrate 210, and the overhanging pattern portion 206 overhangs from the body portion 204, such that one end of the overhanging pattern portion 206 is fixed by being connected to the body portion 204 and the other end is an overhanging free end, i.e., not fixedly connected to the substrate 210.

Referring back to fig. 1, the method 100 further includes a step S120 of irradiating the overhanging pattern portion of the stacked structure with an electron beam to produce a three-dimensional bent structure. In this step, the energy of the electron beam used may be in a range of, for example, 8KeV to 30KeV, and the overhanging pattern portion of the second layer may be globally irradiated or locally irradiated with the electron beam to generate a bent shape in the overhanging pattern portion by inducing stress. It is to be understood that in step S120, also the bulk portion of the layered structure supported on the substrate may be irradiated, which may also induce a stress to bend the overhanging pattern portion. For example, in some embodiments, the overhanging pattern portion and the bulk portion of the stacked structure may be irradiated in a point-by-point scanning along a straight line with an electron beam of nanometer-scale precision and very small beam spot. This is explained in detail below in connection with the examples given in fig. 6 to 8.

Referring to fig. 6, a local area of the overhang pattern portion 206 of the laminate structure 202 may be irradiated with an electron beam to generate a bent structure. Although the specific principles thereof are not fully understood, the inventors believe that when an electron beam irradiates the second metal layer 250 in the stacked structure 202, the electron beam bombards atoms in the second metal layer 250, driving the atoms to move, which may cause the metal atoms in the second metal layer 250 to rearrange, thereby introducing stress into the second metal layer 250, and achieving the curling or bending of the overhanging pattern portion 206. In addition, the thermal effect generated by the electron beam irradiation may also promote the movement of atoms during the electron beam bombardment, and may contribute to the bending effect. The inventors have found that the bending shape of the stack 202 can be retained when the electron beam irradiation is completed and cooled, which indicates that the bending shape is not formed only as a result of the difference in thermal expansion coefficient between the first layer 220 and the second layer 250 under the thermal effect.

The electron beam may be a line beam, for example, a line beam perpendicular to the plane of the paper in fig. 6; or may be a spot beam that may scan the overhanging pattern portion 206 along a straight line (e.g., a straight line perpendicular to the plane of the paper in fig. 6), and the scanning straight line may be moved in a direction to illuminate a local area of the overhanging pattern portion 206, or may even be so moved to illuminate the global area of the overhanging pattern portion 206. In the example shown in fig. 6, by irradiating the heel area of the overhanging pattern portion 206 and the main body portion in the vicinity thereof with an electron beam, a certain degree of bending is generated in the local area. It is understood that the bending angle can be adjusted by adjusting the dose, energy, incident angle, irradiation time of the electron beam, material, thickness, two-dimensional size of the stacked structure, deposition process conditions, and shape and size of the irradiation region, etc. For example, in general, the higher the dose and energy of the electron beam, the longer the irradiation time, and the larger the irradiation area, the more easily a larger bending angle is formed. For another example, when the thickness of the second metal layer 250 is smaller relative to the thickness of the first dielectric layer 220, the formed bending angle may be smaller. As another example, if the electron beam is irradiated in the width direction of the overhang pattern portion 206 perpendicular to the overhang direction (for example, in the direction perpendicular to the paper surface in fig. 6), a larger bending angle can be generated in the entire width range than in the width range of only a part of the electron beam. In some embodiments, multiple localized regions of the overhanging pattern portion 206 may also be illuminated to achieve a desired bend shape. In some embodiments, by selecting different materials for the first layer 220 and the second layer 250,different bending directions can be achieved. For example, when the first layer 220 is made of Al₂O₃When formed, a bend may be created toward the first layer 220 side; when the first layer 220 is formed of SiN, however, a bend toward the second layer 250 side may be generated. In practical applications, suitable conditions may be selected as needed to produce the desired bending direction, angle and shape.

Referring to fig. 7, the overhanging pattern portion 206 and the body portion 204 of the stacked structure 202 may be globally irradiated with an electron beam to produce a meander shape. It will be appreciated that irradiating the overhanging pattern portion 206 may induce a deformation in the overhanging pattern portion 206, while irradiating the body portion 204 may induce an isotropic deformation of the plurality of overhanging pattern portions 206 extending from the body portion 204. In the example of fig. 7, the entire stacked structure 202 can be globally irradiated with a large-area electron beam at the same time, which enables high irradiation efficiency to be achieved, and a three-dimensional bent structure to be obtained in a shorter time.

Fig. 8 shows an embodiment in which a large angle bend is obtained. In the example of fig. 8, the overhanging pattern portion 206 may be scanned along a straight line using an electron beam having a small beam spot size, and the straight line position is shifted from the free end of the overhanging pattern portion 206 toward the fixed end (i.e., the root) of the overhanging pattern portion 206, as indicated by the broken-line arrow in fig. 8. In this way, a bend may be formed over the entire extension of the overhanging pattern portion 206, facilitating a larger degree of bending, e.g. enabling a bending angle of 360 ° or even more.

As can be understood from the examples described above with reference to fig. 6 to 8, in the present invention, the overhanging pattern portion can be irradiated with the electron beam in various flexible ways to obtain a desired bent structure. The metal film in the overhanging pattern part is irradiated by electron beams, atoms in the metal film can be driven to move, so that stress is introduced, and the film is curled or folded towards the three-dimensional direction under the action of the stress. The bending degree, the folding angle and the like of the three-dimensional micro-nano structure can be accurately controlled by controlling the irradiation dose, energy, incident angle, irradiation time of an electron beam, the material, thickness, two-dimensional size and deposition process condition of the laminated structure, the shape and size of an irradiation area and the like, and various three-dimensional configurations can be designed through different combinations of curling and folding. In addition, the deformation range of the curl and the fold can be determined by changing the kind and thickness of the material of the first dielectric layer and/or the material of the second metal layer, the deposition rate, the structure and the size of the overhanging pattern portion of the stacked-layer structure, and the like.

It should be understood that although the first layer 220 is described above as a dielectric layer and the second layer 250 is described as a metal layer, the materials of the first layer 220 and the second layer 250 are not limited to these specific examples. In a more general embodiment, as long as the materials of the first layer 220 and the second layer 250 are different from each other, stress may be induced to bend under irradiation of electron beams. Of course, the inventors have found that the first layer 220 and the second layer 250 are preferably dielectric and metal, respectively, and preferably electron beam direct irradiation of the metal layer, which is more likely to produce a large angle meander structure. Although the specific principles are not yet clear, the inventors believe that it is possible that the large angle bend shape is more likely to be produced because metal atoms are likely to be driven into motion under electron beam bombardment, thereby introducing stress, while the dielectric is likely to produce a stress differential with respect to the metal.

The use of electron beams to induce two-dimensional films and patterns in the present invention results in three-dimensional structures that have many advantages over ion beam induction. The inventors of the present application found in their research that ion beam induced bending techniques have many problems: firstly, this method is limited by the experimental equipment, resulting in higher processing costs; secondly, when the size of the three-dimensional structure is reduced, the processing speed is obviously reduced, and the processing time and the cost are obviously improved; thirdly, all ion-induced assembly is based on an ion implantation process, inevitable sputtering can be caused when impurities are generated due to ion implantation, the incident ions bombard materials, severe physical damage is caused to sensitive materials or ultrathin structures, and the universality is limited; fourthly, the ion beam-based assembly technology has great limitation on the folding directionality, and particularly, the folding components start to block an ion irradiation path after the folding angle reaches 90 degrees, so that further folding is hindered. The above problems can be solved by using an electron beam induction method. The electron beam apparatus is lower in cost than the ion beam apparatus, and the spot size of the electron beam can be easily and precisely controlled, thereby achieving rapid and precise irradiation, and a flexible irradiation manner contributes to obtaining a desired bending shape and a larger bending angle. The electron beam induction mode can also avoid the defects of damage to the surface of the material and ion impurity injection generated inside the material in the ion beam induction mode, and the flexibility of micro-nano structure processing and the low-damage processing capability of the material are improved. Therefore, the electron beam irradiation scheme has important significance in designing the design and processing of the three-dimensional metamaterial with new configuration, high material sensitivity and purity requirements, and has guiding effect on the processing and design of other three-dimensional devices.

Fig. 9 and 10 show photographs of three-dimensional micro-nano bent structures prepared according to some exemplary embodiments of the present invention. In fig. 9, four overhanging pattern portions extending all around from the same main body portion, each realizing a large bending angle, up to about 360 °. In fig. 10, a smaller bending angle is achieved, which is approximately less than 90 °.

The principles of the present invention have been described above by describing some exemplary embodiments in conjunction with the accompanying drawings. It should be understood that these exemplary embodiments should not be construed as limiting the invention. Based on the above teachings, workers skilled in the art will recognize that changes may be made in form and detail without departing from the principles of the invention. For example, the first dielectric layer may be formed over the second metal layer, or the first dielectric layer may be irradiated with an electron beam, which also produces a heating effect, thereby generating deformation by inducing a change in stress. Such changes in form and detail that do not depart from the principles of the invention are intended to be within the scope of the invention as defined by the appended claims.

The preparation method of the three-dimensional micro-nano structure provided by the embodiment of the invention has the advantages of simple process, high success rate, low cost and low requirement on experimental equipment, and the formed structure has the characteristics of rich configuration and accurate and controllable characteristic dimension, and plays an important role in the design and processing of three-dimensional devices in the future.

The foregoing describes the general principles of the present application in conjunction with specific embodiments, however, it is noted that the advantages, effects, etc. mentioned in the present application are merely examples and are not limiting, and they should not be considered essential to the various embodiments of the present application. Furthermore, the foregoing disclosure of specific details is for the purpose of illustration and description and is not intended to be limiting, since the foregoing disclosure is not intended to be exhaustive or to limit the disclosure to the precise details disclosed.

The block diagrams of devices, apparatuses, systems referred to in this application are only given as illustrative examples and are not intended to require or imply that the connections, arrangements, configurations, etc. must be made in the manner shown in the block diagrams. These devices, apparatuses, devices, systems may be connected, arranged, configured in any manner, as will be appreciated by those skilled in the art. Words such as "including," "comprising," "having," and the like are open-ended words that mean "including, but not limited to," and are used interchangeably therewith. The words "or" and "as used herein mean, and are used interchangeably with, the word" and/or, "unless the context clearly dictates otherwise. The word "such as" is used herein to mean, and is used interchangeably with, the phrase "such as but not limited to".

It should also be noted that in the devices, apparatuses, and methods of the present application, the components or steps may be decomposed and/or recombined. These decompositions and/or recombinations are to be considered as equivalents of the present application.

The previous 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 generic principles defined herein may be applied to other aspects without departing from the scope of the application. Thus, 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.

The foregoing description has been presented for purposes of illustration and description. Furthermore, the description is not intended to limit embodiments of the application to the form disclosed herein. While a number of example aspects and embodiments have been discussed above, those of skill in the art will recognize certain variations, modifications, alterations, additions and sub-combinations thereof.

Claims

1. A method of fabricating a three-dimensional bent structure using electron beams, comprising:

preparing a laminated structure including at least a first layer and a second layer on the first layer, the laminated structure having a body portion supported on a substrate and at least one overhanging pattern portion extending from the body portion;

irradiating the overhanging pattern portion with an electron beam to bend the overhanging pattern portion, thereby obtaining a three-dimensional bent structure.

2. The method of claim 1, wherein the first layer is formed of a dielectric material and the second layer is formed of a metallic material.

3. The method of claim 1, wherein preparing a laminate structure comprises:

forming the first layer on the substrate;

etching the first layer to form a body portion and an overhanging pattern portion extending from the body portion;

forming a sacrificial layer pattern on the substrate, the sacrificial layer pattern exposing a body portion and an overhang pattern portion of the first layer;

depositing a second layer on the sacrificial layer pattern and the body portion and the overhanging pattern portion of the first layer;

removing the sacrificial layer pattern and a portion of the second layer deposited on the sacrificial layer pattern to obtain the stacked structure; and

removing a portion of the substrate underlying an overhanging pattern portion of the stacked structure such that the body portion is supported on the substrate and the overhanging pattern portion overhangs from the body portion.

4. The method of claim 1, wherein preparing a laminate structure comprises:

forming a first layer and a second layer on the first layer on the substrate;

etching the first layer and the second layer to form a stacked structure including a body portion and an overhanging pattern portion extending from the body portion; and

5. The method of claim 1, wherein preparing a laminate structure comprises:

transferring a first layer onto the substrate, the substrate having at least one open area, the first layer covering the open area of the substrate;

etching the first layer to form a body portion supported by the substrate and at least one overhanging pattern portion extending from the body portion into an open region of the substrate; and

depositing the second layer on the first layer.

6. The method of claim 1, wherein preparing a laminate structure comprises:

transferring a multilayer film comprising at least a first layer and a second layer on the first layer onto the substrate, the substrate having at least one open area, the multilayer film covering the open area of the substrate; and

etching the multilayer film to form a body portion supported by the substrate and at least one overhanging pattern portion extending from the body portion into an opening area of the substrate.

7. The method of claim 1, wherein irradiating the overhanging pattern portion with an electron beam comprises:

globally or locally irradiating an overhanging pattern portion of the second layer with an electron beam.

8. The method of claim 7, wherein globally or locally irradiating the overhanging pattern portion of the second layer with an electron beam comprises:

scanning all or a partial area of the overhanging pattern portion of the second layer point by point with an electron beam.

9. A three-dimensional bent structure made using the method of any of claims 1-8, having a laminate structure comprising at least a first layer and a second layer on the first layer, the laminate structure comprising a body portion and at least one three-dimensional bent portion extending from the body portion.

10. The three-dimensional bent structure according to claim 9, wherein the thickness of each of the first and second layers is in the range of 1nm to 100 μ ι η, preferably in the range of 1nm to 1 μ ι η, more preferably in the range of 1nm to 100 nm.