Micro-nano scale mechanical interlocking structure and preparation method thereof
By designing a hook-shaped nested interlocking structure between the micro/nano silicon wire and the pillar, the problem of poor contact between the micro/nano device and the substrate was solved, achieving stable suspension and stress release of the device, and improving the stability and durability of the device.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NANJING UNIV
- Filing Date
- 2023-05-22
- Publication Date
- 2026-06-09
AI Technical Summary
In the existing technology, suspended devices manufactured by transferring micro- and nano-silicon wires have problems such as poor contact with the substrate and easy vibration detachment, which limits the performance stability and application fields of the devices.
A micro-nano scale mechanical interlocking structure is adopted, which utilizes the nested interlocking design of the hook structure of silicon nanowires and micro-nano pillars. Grooves and pillars are formed on the substrate through photolithography and etching processes, and the interlocking is achieved by combining wire picking process.
This technology enables stable suspension of micro- and nanowire devices during use, reducing the risk of detachment, and effectively releases stress when subjected to tensile deformation, thereby improving the stability and durability of the devices.
Smart Images
Figure CN116854021B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to micro-nano electromechanical systems, and more particularly to a micro-nano scale mechanical interlocking structure and its fabrication method. Background Technology
[0002] Silicon-based micro / nano-electromechanical systems (MEMS) are a novel technology that integrates microelectronics, micromechanics, optics, and materials science. They have a wide range of applications, including the automotive, medical and health monitoring, communications, and consumer electronics industries such as mobile phones and game consoles. They offer advantages such as miniaturization, integration, high reliability, high precision, and low cost. Based on the customizable morphology and easy transfer and suspension capabilities of silicon micro / nanowires, they have been widely used in the fabrication of galvanometers, accelerators, micro / nano robotic arms, and biological probes.
[0003] However, the inventors of this application have discovered that suspended devices manufactured by the transfer of micro- and nano-silicon wires have always suffered from poor contact with the substrate and are prone to vibration and detachment from the substrate during use, which severely limits the performance stability and application areas of the devices.
[0004] An article published in *National Science Review* (Ji S, Chen X. Enhancing the interfacial binding strength between modular stretchable electronic components[J]. *National Science Review*, 2023, 10(1): nwac172.) reviews various methods for enhancing the interfacial bonding strength between stretchable electronic components. One method involves forming covalent bonds through chemical methods. This method is suitable for specific materials or requires the introduction of other substances, but it is not suitable for the contact between silicon-based nanowires and substrates, and may even affect device performance. Another method is mechanical interlocking. The article mentions two types of mechanical interlocking: one is to enhance the bonding strength through polymer chain entanglement, since most stretchable components are polymers. This method is only suitable for polymers and is difficult to use on devices made of inorganic materials. The other method is to form a micro-root-like structure. This method focuses on the design of the microstructure between the interfaces, mainly by increasing the interfacial contact area and friction to enhance the bonding strength. This method is not suitable for the bonding between nanowire structures and interfaces. The methods introduced in this review are mainly applicable to materials related to stretchable devices, and focus primarily on enhancing the bonding strength of the microstructure between interfaces.
[0005] Therefore, there is an urgent need to develop a simple, efficient and reliable solution for contact and fixation between nanowires and substrates. Summary of the Invention
[0006] To address the problems and shortcomings of the existing technology, this invention provides a micro / nano-scale mechanical interlocking structure, primarily utilizing the morphological design of silicon nanowires and the matching between micro / nano pillars to achieve interlocking through nested mechanical structures. This application also relates to a method for fabricating this interlocking structure.
[0007] The present invention provides a micro-nano scale mechanical interlocking structure, characterized in that: it includes at least one micro-nano pillar with a predetermined depth disposed on a substrate, and at least one micro-nano silicon wire with a hook-shaped structure. The micro-nano pillar is etched with grooves, and the hook-shaped structure of the micro-nano silicon wire matches the shape and number of the micro-nano pillar, and is nested and interlocked with the grooves on the micro-nano pillar.
[0008] Preferably, the preset depth range of the micro-nano pillars is 200 nanometers to 500 micrometers, and the shape includes, but is not limited to, cylinders and cuboids.
[0009] Preferably, the diameter of the micro / nano silicon wire ranges from 10 nanometers to 500 micrometers, and its hook-shaped structure includes, but is not limited to, circular and square shapes.
[0010] This invention also discloses a method for fabricating a micro / nano-scale mechanical interlocking structure, characterized by comprising the following steps:
[0011] The first step is to define the pillar shape on the substrate using photolithography, and then use an etching method to prepare micro-nano pillars of a set depth. The micro-nano pillars are etched to form grooves.
[0012] The second step is to prepare nanowires with hook-like structures that match the size and distribution of the micro- and nano-pillars;
[0013] The third step involves using a wire-picking process to nest and interlock the hook-shaped micro / nano silicon wires obtained in step two with the pillars obtained in step one.
[0014] As a preferred embodiment, the method for preparing the hook-shaped micro / nano silicon wires in the second step is as follows:
[0015] Using a planar nanowire guided growth process, a pre-defined hook-shaped guide trench is formed on the surface of a silicon oxide substrate through photolithography and etching. Then, a catalytic metal strip is deposited through photolithography and evaporation processes. The substrate is placed in a plasma-enhanced chemical deposition system, and hydrogen plasma treatment is used to remove the oxide layer on the surface of the catalytic metal and form metal droplets. After depositing amorphous silicon, it is annealed to grow silicon nanowires with hook-like structures.
[0016] Alternatively, nanosilicon wires with hook-like structures that match the size and distribution of the pillars can be prepared by combining electron beam lithography with etching processes.
[0017] Alternatively, micron-sized silicon wires with hook-like structures that match the size and distribution of the pillars can be fabricated using conventional photolithography combined with etching processes.
[0018] The technical solution provided in this application has at least the following technical effects or advantages:
[0019] 1. The mechanical interlocking structure of the present invention is made of traditional silicon material, and the manufacturing method is simple and compatible with traditional silicon processes.
[0020] 2. This invention cleverly combines micro-nanowire hooks with pillars to form a stable mechanical interlocking structure, effectively solving the problem of one-dimensional contact difference between traditional straight-shaped micro-nanowires and the substrate, making suspended micro-nano devices more stable during use.
[0021] 3. The mechanical interlocking structure of the present invention allows the hook structure to rotate slightly along the column when the micro-nanowire device is subjected to large tensile deformation, thereby better releasing stress and reducing damage to the micro-nanowire device. Attached Figure Description
[0022] Figure 1 This is a flowchart illustrating the fabrication process of the mechanical interlocking structure with a pair of columns in Embodiment 1 of the present invention.
[0023] Figure 2 This is a flowchart illustrating the fabrication process of the columns in the mechanical interlocking structure with a pair of columns in Embodiment 1 of the present invention.
[0024] Figure 3 This is a scanning electron microscope image of the mechanical interlock structure in Embodiment 1 of the present invention;
[0025] Figure 4 This is a flowchart illustrating the fabrication of a micro / nano-scale mechanical interlocking structure with three pillars and three hook-shaped nanowires at its ends in Embodiment 2 of the present invention.
[0026] Figure 5 This is a rendering of the micro-nano scale mechanical interlocking structure with three pillars prepared in Embodiment 2 of the present invention;
[0027] Figure 6 This is a schematic diagram of a micro-nano scale mechanical interlocking structure with two pillars at each end, prepared in Embodiment 3 of the present invention. Detailed Implementation
[0028] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.
[0029] Example 1: As Figures 1-3As shown: This embodiment provides a method for fabricating an interlocking structure at both ends, including a pair of micro / nano pillars fabricated on a substrate and a bent micro / nano silicon wire with a hook-like structure at each end. The hook-like structures of the micro / nano silicon wires match the shape and number of the micro / nano pillars and are nested and interlocked with the micro / nano pillars.
[0030] In this embodiment, the depth of the micro-nano pillar is 20 micrometers, and the shape is a cylinder with grooves.
[0031] The diameter of the micro / nano silicon wire in this embodiment is 120 nanometers.
[0032] This embodiment also provides a method for fabricating the above-mentioned micro / nano-scale mechanical interlocking structure, such as... Figure 1 In Figure 1 a- Figure 1 As shown in d, the specific steps include:
[0033] The first step involves forming guide trenches with hook-like structures at both ends on the surface of a silicon oxide substrate through photolithography and etching. Then, a catalytic metal strip is formed through photolithography and deposition. The strip is placed in PECVD, where hydrogen plasma treatment removes the oxide layer on the surface of the catalytic metal and forms metal droplets. Amorphous silicon is deposited and then annealed to grow silicon nanowires with a diameter of 120 nm.
[0034] The second step involves using photolithography to define pillar shapes with a diameter of 5 micrometers on the silicon wafer surface, spaced 50 micrometers apart. Two pillars are then fabricated using deep silicon etching. Figure 2 a, Figure 2 As shown in b.
[0035] The third step involves using optical fibers to lift the silicon nanowires grown in the first step and transfer them to the substrate from the second step. The hook-like structures at both ends are then nested into the grooves on the end posts to achieve interlocking. Figure 3 This is a scanning electron microscope image of the interlocking structure.
[0036] The technical solutions described in the embodiments of this application have at least the following technical effects or advantages:
[0037] 1) The interlocking structure at both ends allows the silicon nanowire device structure to be stably suspended and not easily detached from the substrate;
[0038] 2) The interlocking structure at both ends allows the hook structure to rotate slightly along the column when the silicon nanowire device is subjected to large tensile deformation, which better releases stress and reduces damage to the silicon nanowire device.
[0039] 3) The two end silicon nanowire hooks in the interlocking structure can be grown and prepared at one time with the rest of the nanowire, and the interlocking structure can be obtained by simple transfer and matching column suspension.
[0040] Example 2: This example provides a method for forming a mechanical self-locking mechanism with three uprights and three hook-like structures; the specific steps include:
[0041] The first step involves using electron beam lithography to define a 500-nanometer-wide strip with three hook-like structures at its ends on an SOI substrate. Dry etching is then performed down to the oxide layer, followed by wet etching with hydrofluoric acid solution to release the nanowires. Figure 4 of Figure 4 a, Figure 4 As shown in b, the nanowires have a diameter of approximately 500 nanometers. The semi-circular hook structure matches the shape and size of the pillars, with a diameter of approximately 6 micrometers. Figure 4 R1) in a;
[0042] The second step involves using a combination of photolithography and etching to create three pillars that match the nanowire hook structure obtained in the first step. The pillars are approximately 40 micrometers deep and 6 micrometers in diameter.
[0043] The third step involves using optical fibers to lift the silicon nanowires grown in the first step and transfer them to the substrate from the second step. The hook-like structures at both ends of the nanowires are then nested with the ends of the pillars to achieve interlocking. Figure 5 This is an image showing the effect of the interlocking structure.
[0044] The multiple interlocking structures prepared by the technical solution in this application embodiment further restrict the degree of freedom of movement of the micron-sized silicon wire, making its contact with the column more secure.
[0045] Example 3: This example describes a method for preparing a mechanically self-locking structure with two pillars and two hook-like structures. The preparation method is similar to that in Examples 1 and 2, and will not be described in detail. The image of the interlocking structure is shown below. Figure 6 As shown. The interlocking micro / nanowire structure of the present invention is made of traditional silicon material. The preparation process is simple and compatible with mature silicon processes. Moreover, the obtained interlocking structure allows the micro / nanowire structure to withstand large external forces without falling off.
[0046] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements can be made without departing from the principle of the present invention, and these improvements should also be considered within the scope of protection of the present invention.
Claims
1. A method for fabricating a micro / nano-scale mechanical interlocking structure, characterized in that: Includes the following steps: The first step is to define the pillar shape on the substrate using photolithography, and then use an etching method to prepare micro-nano pillars of a set depth. The micro-nano pillars are etched to form grooves. The second step is to prepare micro-nano silicon wires with hook-like structures that match the size and distribution of the micro-nano pillars; The third step involves using a wire-picking process to nest and interlock the micro-nano silicon wires with hook-like structures obtained in step two with the pillars obtained in step one. The second step involves the preparation of micro / nano silicon wires with hook-like structures as follows: Using a planar nanowire guided growth process, a pre-defined hook-shaped guide trench is formed on the surface of a silicon oxide substrate through photolithography and etching. Then, a catalytic metal strip is deposited through photolithography and evaporation processes. The substrate is placed in a plasma-enhanced chemical deposition system, and hydrogen plasma treatment is used to remove the oxide layer on the surface of the catalytic metal and form metal droplets. After depositing amorphous silicon, it is annealed to grow silicon nanowires with hook-like structures. Alternatively, nanosilicon wires with hook-like structures that match the size and distribution of the pillars can be prepared by combining electron beam lithography with etching processes. Alternatively, micron-sized silicon wires with hook-like structures that match the size and distribution of the pillars can be fabricated using conventional photolithography combined with etching processes.
2. A micro / nano-scale mechanical interlocking structure prepared by the method described in claim 1, characterized in that: It includes at least one micro / nano pillar with a predetermined depth disposed on a substrate, and at least one micro / nano silicon wire with a hook-like structure. The micro / nano pillar is etched to form a groove. The hook-like structure of the micro / nano silicon wire matches the shape and number of the micro / nano pillar and is nested and interlocked with the groove on the micro / nano pillar.
3. The micro-nano scale mechanical interlocking structure according to claim 2, characterized in that: The preset depth range of the micro-nano pillars is 200 nanometers to 500 micrometers, and the shapes include, but are not limited to, cylinders and cuboids.
4. The micro-nano scale mechanical interlock structure according to claim 2, characterized in that: The diameter of the micro / nano silicon wires ranges from 10 nanometers to 500 micrometers, and their hook-like structures include, but are not limited to, circles and squares.