A thin-film mechanical oscillator with an anti-adsorption structure and its preparation method

Abstract

This application discloses a thin-film mechanical oscillator with an anti-adsorption structure and its preparation method. The thin-film mechanical oscillator includes: a substrate; a first metallization layer grown on one side of the substrate; a first sacrificial layer grown on the first metallization layer and having a periodically arranged columnar structure; a second sacrificial layer grown on the first sacrificial layer and serving as a support structure located at the edge of the first sacrificial layer; a high-tensile stress thin film layer grown on the second sacrificial layer, the high-tensile stress thin film layer having a suspended thin film region and a non-suspended thin film region, and a cavity between the high-tensile stress thin film layer and the substrate that allows the suspended thin film region to be suspended; the periodically arranged columnar structure is located in the region of the cavity; the non-suspended thin film region is supported by the first and second sacrificial layers; and a second metallization layer grown on the high-tensile stress thin film layer and located at the center of the suspended thin film region and the non-suspended thin film region.

Description

Technical Field

[0001] This application relates to the field of quantum device technology, specifically to a thin-film mechanical oscillator with an anti-adsorption structure and its preparation method. Background Technology

[0002] The core of cavity optomechanics is the study of the interaction between light fields and matter motion mediated by radiation pressure. Due to the need for highly sensitive optical detection of minute forces, displacements, masses, and accelerations; and because cavity optomechanics holds promise for using light to manipulate and detect mechanical motion in quantum states, thereby generating nonclassical states of light and mechanical motion, interest in cavity optomechanics has grown rapidly. Furthermore, cavity optomechanics also has important applications in signal conversion between optical and microwave frequency bands.

[0003] Mechanical oscillators, when acted upon by an intracavity optical field, play a crucial role in cavity optomechanics research. The optomechanical coupling system of a mechanical oscillator in a high-tensile-stress thin film is one of the key research directions in cavity optomechanics. This system achieves manipulation and readout of the mechanical oscillator's state through the interaction of a microwave field or optical field with the thin-film mechanical oscillator. When the mechanical oscillator is manipulated and cooled to the quantum region, this system has broad application prospects in the field of quantum information technology, including quantum information storage, quantum signal conversion, quantum sensing, and quantum precision measurement.

[0004] Currently, in this type of optomechanical coupling system based on a high-tensile-stress thin film mechanical oscillator, when using a microwave field for state control and readout, the thin-film mechanical oscillator and the microwave control and readout structure can be either discrete or integrated. To achieve high-performance control and readout of the thin-film mechanical oscillator by the microwave field, both forms require a sufficiently close spatial distance between the thin-film mechanical oscillator and the control and readout structure, typically on the order of hundreds of nanometers. However, the area of ​​the thin-film mechanical oscillator itself is on the order of square millimeters, making it very susceptible to adsorption onto the microwave control and readout structure due to factors such as vibration, electrostatic forces, and the surface tension of the liquid involved in the fabrication process, leading to device failure.

[0005] Therefore, how to prevent the suspended thin-film mechanical oscillator from being adsorbed onto the microwave-controlled reading structure is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] To address the aforementioned deficiencies in this field, this application aims to provide a thin-film mechanical oscillator with an anti-adsorption structure and its preparation method, which can prevent the problem of adsorption of the suspended thin-film mechanical oscillator by the microwave-controlled reading structure in a high-tensile-stress thin-film mechanical oscillator photomechanical coupling system.

[0007] According to one aspect of this application, a thin-film mechanical oscillator with an anti-adsorption structure is provided, comprising:

[0008] Substrate;

[0009] The first metallization layer is grown on one side of the substrate.

[0010] The first sacrificial layer is grown on the first metallization layer and is a periodically arranged columnar structure;

[0011] The second sacrificial layer grows on the first sacrificial layer and serves as a support structure located at the edge of the first sacrificial layer;

[0012] A high-stress thin film layer is grown on a second sacrificial layer. The high-stress thin film layer has a suspended thin film region and a non-suspended thin film region. There is a cavity between the high-stress thin film layer and the substrate that allows the suspended thin film region to be suspended. Periodically arranged columnar structures are located in the cavity region. The non-suspended thin film region is supported by the first sacrificial layer and the second sacrificial layer.

[0013] The second metallization layer is grown on the high-tensile-stress thin film layer and is located in the center of the suspended thin film region and the non-suspended thin film region.

[0014] According to some embodiments of this application, the material of the first sacrificial layer is different from the material of the second sacrificial layer.

[0015] The materials for the first and second sacrificial layers can be either amorphous silicon or silicon dioxide.

[0016] According to some embodiments of this application, the thickness of the first sacrificial layer is 20-100 nm;

[0017] The thickness of the second sacrificial layer is 100-500 nm.

[0018] According to some embodiments of this application, the thickness of the substrate is 200-500 μm;

[0019] The thickness of the first metallization layer is 50-200 nm;

[0020] The thickness of the second metallization layer is 50-200 nm;

[0021] The thickness of the high-tensile-stress thin film layer is 50-100 nm.

[0022] According to some embodiments of this application, the width of each periodically arranged columnar structure is 200-1000 nm, and the interval between each period is 5-20 μm.

[0023] According to some embodiments of this application, the substrate includes: a high-resistivity silicon substrate or a sapphire substrate;

[0024] The materials for the first and second metallization layers include niobium or aluminum;

[0025] Materials for high-tensile-stress thin film layers include silicon nitride or silicon carbide.

[0026] According to another aspect of this application, a method for preparing a thin-film mechanical oscillator with an anti-adsorption structure is also provided, comprising:

[0027] A first metallization layer is grown on the surface of a substrate.

[0028] A first sacrificial layer and a second sacrificial layer are sequentially grown on the surface of the first metallization layer;

[0029] Patterned etching removes the edge regions of the first metallization layer, the first sacrificial layer, and the second sacrificial layer, exposing the edge of the substrate.

[0030] A high-tensile-stress thin film layer is grown on the surface of the second sacrificial layer and at the edge of the substrate.

[0031] Patterned etching removes part of the first sacrificial layer, the second sacrificial layer, and the high-tensile stress thin film layer, exposing part of the first metallization layer;

[0032] A second metallization layer is grown on the surface of the high-tensile stress thin film layer and on the surface of the exposed first metallization layer;

[0033] The second metallization layer is etched to obtain the pattern of the second metallization layer;

[0034] Patterned etching of the second sacrificial layer and the high-tensile stress thin film layer yields periodically arranged release windows, which are circular with a diameter of 2-8 μm and a period of 5-20 μm.

[0035] A portion of the first sacrificial layer is removed by etching with a release window and a first wet etching solution to obtain a periodically arranged columnar structure;

[0036] By removing part of the second sacrificial layer through the release window and the second wet etching solution, a support structure and cavity located at the edge of the first sacrificial layer are obtained, so that the high-tensile stress thin film layer forms a suspended thin film region and a non-suspended thin film region, resulting in a thin film mechanical oscillator with an anti-adsorption structure.

[0037] According to some embodiments of this application, the materials of the first sacrificial layer and the second sacrificial layer are different;

[0038] The materials for the first sacrificial layer and the second sacrificial layer are selected from amorphous silicon or silicon dioxide.

[0039] When the sacrificial layer material is amorphous silicon, the wet etching solution is an aqueous KOH solution; when the sacrificial layer material is silicon dioxide, the wet etching solution is a BOE solution.

[0040] According to some embodiments of this application, the thickness of the first sacrificial layer is 20-100 nm;

[0041] The thickness of the second sacrificial layer is 100-500 nm;

[0042] The thickness of the substrate is 200-500 μm;

[0043] The thickness of the first metallization layer is 50-200 nm;

[0044] The thickness of the second metallization layer is 50-200 nm;

[0045] The thickness of the high-tensile-stress thin film layer is 50-100 nm;

[0046] Each periodically arranged columnar structure has a width of 200-1000 nm, and the interval between each period is 5-20 μm.

[0047] According to some embodiments of this application, the substrate includes: a high-resistivity silicon substrate or a sapphire substrate;

[0048] The materials for the first and second metallization layers include niobium or aluminum;

[0049] Materials for high-tensile-stress thin film layers include silicon nitride or silicon carbide.

[0050] Compared with the prior art, this application has at least the following beneficial effects:

[0051] This application provides a thin-film mechanical oscillator with an anti-adsorption structure. The support pillar is prepared by a two-layer sacrificial layer structure. The support pillar is located in the cavity between the high-tensile stress thin film layer and the substrate, which can suspend the suspended thin film area and play a supporting role. This prevents the suspended thin-film mechanical oscillator in the device from being adsorbed by the bottom microwave-controlled reading structure. At the same time, it can also automatically prevent thin film adsorption problems caused by external vibration or electrostatic attraction after the sample preparation is completed. Attached Figure Description

[0052] Figure 1 This is a schematic diagram of the fabrication process of a thin-film mechanical oscillator with an anti-adsorption structure, which is an example embodiment of this application.

[0053] Figure 2 This is a front view and an enlarged schematic diagram of the release window of a thin-film mechanical oscillator with an anti-adsorption structure, as shown in the example embodiment of this application.

[0054] Figure 3 This is a graph showing the relationship between the single-photon coupling intensity g0 of the device in this application and the total thickness d of the sacrificial layer material 3 and the sacrificial layer material 4.

[0055] Figure 4 This is a diagram illustrating the automatic anti-adsorption effect of the thin-film mechanical oscillator with an anti-adsorption structure according to this application.

[0056] Figure 5 The image shows a test diagram of the adsorption effect of a thin-film mechanical oscillator, which is an example of the comparative features of this application. Detailed Implementation

[0057] The technical solution of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0058] It should be particularly noted that similar substitutions and modifications made to this application are obvious to those skilled in the art, and they are all considered to be included in this application. Those skilled in the art can obviously make modifications or appropriate alterations and combinations to the methods and applications described herein without departing from the content, spirit, and scope of this application to implement and apply the technology of this application. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0059] Unless otherwise specified, this application is conducted under standard conditions or conditions recommended by the manufacturer. The raw materials or excipients used, as well as the reagents or instruments used, whose manufacturers are not specified, are all conventional products that can be obtained commercially.

[0060] The following is a detailed description of this application.

[0061] This application reveals that in the current process of fabricating a single-layer chip integrated thin-film mechanical oscillator, when the sacrificial layer is released in a gas-phase manner, the reacting gas is in an ionized state with a bias voltage, which can cause certain damage to the thin-film oscillator made of materials such as silicon nitride or silicon carbide. Furthermore, when releasing the sacrificial layer using a wet etching process with a solution, due to the surface tension of the liquid, the drying process after release can cause the thin-film oscillator to be adsorbed onto the bottom electrode structure, resulting in chip failure. Therefore, supercritical drying equipment is required for drying.

[0062] Currently, in single-layer chip integrated thin-film mechanical oscillators and traditional flip-chip bonded thin-film mechanical oscillator structures with readout structures, the distance between the vibrating thin film and the bottom electrode needs to be on the order of hundreds of nanometers, while the area of ​​the thin-film mechanical oscillator itself is on the order of square millimeters. When the device is subjected to external vibration or electrostatic attraction between the thin film and the bottom electrode, the thin film is still easily adsorbed onto the bottom electrode, causing chip failure.

[0063] To address the aforementioned technical issues, this application employs a two-layer sacrificial layer and a step-by-step release process to form a columnar structure with a nanoscale array. This columnar structure automatically prevents the suspended thin-film mechanical oscillator in the device from being adsorbed by the bottom microwave-controlled readout structure. Compared to existing technologies, this application's solution can release the sacrificial layer via a wet solution method and avoids film adsorption problems caused by liquid surface tension without supercritical drying. Furthermore, it automatically prevents film adsorption problems caused by external vibrations or electrostatic attraction after sample preparation. Based on this, this technical solution can also improve the stability and yield of single-layer chip integrated thin-film mechanical oscillator devices, which is beneficial for the large-scale integration of devices.

[0064] Specifically, in some examples, such as Figure 1 As shown, this application provides a method for preparing a thin-film mechanical oscillator with an anti-adsorption structure, comprising:

[0065] A first metallization layer 2 is grown on the surface of a substrate 1; a first sacrificial layer 3 and a second sacrificial layer 4 are sequentially grown on the surface of the first metallization layer 2; the edge regions of the first metallization layer 2, the first sacrificial layer 3, and the second sacrificial layer 4 are removed by patterning etching, exposing edge a of the substrate 1; a high-tensile stress thin film layer 5 is grown on the surface of the second sacrificial layer 4 and the edge of the substrate 1; a portion of the first sacrificial layer 3, the second sacrificial layer 4, and the high-tensile stress thin film layer 5 is removed by patterning etching, exposing portion b of the first metallization layer 2; the surface of the high-tensile stress thin film layer 5 and the exposed surface of the first metallization layer 2 are then exposed. A second metallization layer 6 is grown on the surface; the second metallization layer 6 is etched to obtain a pattern of the second metallization layer; the second sacrificial layer 4 and the high-tensile stress thin film layer 5 are patterned and etched to obtain periodically arranged release windows c; a portion of the first sacrificial layer 3 is removed by etching through the release windows and the first wet etching solution to obtain a periodically arranged columnar structure d; a portion of the second sacrificial layer 4 is removed by etching through the release windows and the second wet etching solution to obtain a support structure e and a cavity f located at the edge of the first sacrificial layer 3, so that the high-tensile stress thin film layer 5 forms a suspended thin film region and a non-suspended thin film region, thus obtaining a thin film mechanical oscillator with an anti-adsorption structure.

[0066] In some examples, the first sacrificial layer is made of amorphous silicon, which eventually forms a periodically arranged nanoscale array of columnar structures in the device. This columnar structure automatically prevents the suspended thin-film mechanical oscillators in the device from being adsorbed by the bottom microwave-controlled readout structure.

[0067] The second sacrificial layer is made of silicon dioxide. After the sacrificial layer is completely released, it ensures that the high-tensile stress film 5 is in a suspended state to form a thin-film mechanical oscillator.

[0068] In some examples, the thickness of the first sacrificial layer is 20-100 nm, which can be adjusted according to the design requirements capacitance value between the second metallization layer 6 and the first metallization layer 2.

[0069] The thickness of the second sacrificial layer is 100-500nm, which can be adjusted according to the design requirements of the capacitance value between the second metallization layer 6 and the first metallization layer 2.

[0070] In some examples, the thickness of the substrate is 200-500 μm; the thickness of the first metallization layer is 50-200 nm; and the thickness of the second metallization layer is 50-200 nm.

[0071] In some examples, the materials of the high-tensile-stress thin film layer include silicon nitride or silicon carbide, and the in-plane tensile stress of the high-tensile-stress thin film layer can be greater than 2 GPa.

[0072] The thickness of the high-tensile-stress thin film layer is 50-100nm, which can be adjusted according to the in-plane tensile stress requirements and the mechanical vibration loss requirements of the thin film. When a higher in-plane tensile stress or a lower mechanical vibration loss of the thin film is required, a smaller thickness is selected, and vice versa.

[0073] In some examples, the width of each of the periodically arranged columnar structures is 200-1000 nm, and the arrangement period is 5-20 μm.

[0074] In some examples, the substrate includes a high-resistivity silicon substrate or a sapphire substrate with low microwave loss, ensuring a high quality factor for the device's microwave-controlled readout structure.

[0075] The materials of the first metallization layer and the second metallization layer include niobium or aluminum, which are semiconductor micro / nano-processing metal materials with superconducting properties at low temperatures.

[0076] In some examples, based on the above preparation method, this application also provides a thin-film mechanical oscillator with an anti-adsorption structure, comprising: a substrate 1, a first metallization layer 2, a first sacrificial layer 3, a second sacrificial layer 4, a high-tensile stress thin film layer 5, and a second metallization layer 6.

[0077] The substrate comprises: a first metallization layer 2, grown on one side of the substrate; a first sacrificial layer 3, grown on the first metallization layer and forming a periodically arranged columnar structure d; a second sacrificial layer 4, grown on the first sacrificial layer and serving as a support structure e located at the edge of the first sacrificial layer; a high-tensile stress thin film layer 5, grown on the second sacrificial layer, having a suspended thin film region and a non-suspended thin film region, and a cavity f between the high-tensile stress thin film layer and the substrate that allows the suspended thin film region to be suspended; the periodically arranged columnar structure d located in the region of the cavity f; the non-suspended thin film region being supported by a portion of the first and second sacrificial layers; and a second metallization layer 6, grown on the high-tensile stress thin film layer and located at the center of the suspended thin film region and the non-suspended thin film region.

[0078] like Figure 2 The diagram shows a front view of a thin-film mechanical oscillator with an anti-adsorption structure and an enlarged schematic diagram of the release window in an example embodiment of this application. In the diagram, A is the LC cavity reading structure; B is the inductor L; C is the capacitor C; and D is the thin-film oscillator region (i.e., the suspended thin-film region).

[0079] In some examples, the thin-film mechanical oscillator with anti-adsorption structure of this application operates on the following principle:

[0080] The suspended high-tension film 5, relying on its own in-plane tensile stress, can remain in a taut state to form a thin-film mechanical oscillator. The size of this thin-film mechanical oscillator is determined by the periodically distributed sacrificial layer release windows. For example, when the total size of the periodic release windows is approximately a square with a side length of 500 μm, and if the in-plane tensile stress of the high-tension film 5 is approximately 1.1 GPa, then the fundamental mode resonant frequency of the thin-film mechanical oscillator formed by the suspended portion of the high-tension film 5 is... Approximately 750kHz.

[0081] The meandering portion of the patterned second metallization layer 6 forms an inductor L, and the middle portion of the patterned second metallization layer 6 and the bottom first metallization layer 2 form a parallel plate capacitor C. The parallel plate capacitor and the inductor L are connected in parallel to form an LC resonant cavity. The parallel plate capacitor C is composed of the area S of the middle portion of the second metallization layer 6, the total thickness d of the first sacrificial layer material 3 and the second sacrificial layer material 4, and the thickness of the high-tensile stress film 5. The dielectric constant E of the high-tensile-stress thin film is determined by its dielectric constant. ,in Since the vacuum dielectric constant is 0, the frequency of the LC resonant cavity is 0. .

[0082] After the device is fabricated, the first sacrificial layer material 3 and the second sacrificial layer material 4 in the middle of the parallel plate capacitor C have been released and removed. When the thin-film mechanical oscillator composed of the high-tensile stress film 5 vibrates up and down, it vibrates up and down along with the second metallization layer 6 on the upper surface, which is equivalent to changing the total thickness d of the first sacrificial layer material 3 and the second sacrificial layer material 4. Therefore, the value of the parallel plate capacitor C is affected by the vibration of the thin-film mechanical oscillator composed of the high-tensile stress film 5, thereby realizing the coupling between the thin-film mechanical oscillator and the LC resonant cavity, corresponding to the single-photon coupling strength. ,in The zero-point fluctuation amplitude of the fundamental resonance mode of the thin-film mechanical oscillator. Where h is Planck's constant, The effective mass of the vibration mode of a thin-film mechanical oscillator, for example, a square thin-film mechanical oscillator with a side length of approximately 500 μm, is the effective mass of its fundamental resonance mode when the in-plane tensile stress of a 100 nm thick silicon nitride film with high tensile stress is approximately 1.1 GPa. The area S of the middle portion of the second metallization layer 6 is selected as... Then, the single-photon coupling strength between the thin-film mechanical oscillator and the LC resonant cavity can be theoretically calculated. As the total thickness d of the first sacrificial layer material 3 and the second sacrificial layer material 4 changes, the calculation results are as follows: Figure 3 As shown, therefore, it can be determined based on the single-photon coupling strength. The design requirements adjust the total thickness d of the first sacrificial layer material 3 and the second sacrificial layer material 4.

[0083] like Figure 3 The figure shown is a graph showing the relationship between the single-photon coupling intensity g0 of the device in this application and the total thickness d of the first sacrificial layer material 3 and the second sacrificial layer material 4.

[0084] When the thin-film mechanical oscillator undergoes vertical deformation perpendicular to the surface due to external vibration or electrostatic attraction, the sacrificial layer material 3 retains a periodically distributed nanoscale support structure. As the film deforms towards the bottom, it first contacts this support structure, thus preventing the film from further contacting the bottom metallization layer 2 and being completely adsorbed. The total size of the periodic release window on the high-tensile stress film 5 is the side length. The arrangement interval period in both directions is 1. After the release is complete, the sacrificial layer material 3 at the bottom of the release window is retained. The width of the support structure. The total attractive force formed by the electrostatic force between the high-tensile stress film 6 and the bottom sacrificial layer material 3 and metallization layer 2, the pressure difference formed by atmospheric pressure after adsorption, and the molecular forces between the materials is proportional to the contact area. Therefore, the ratio of the mutual attractive force between the high-tensile stress film 6 and the periodic support structure to that without the support structure is: Therefore, the mutual attraction force can be greatly reduced. Thus, when the high-stress film deforms downward, it can generate an upward elastic force through its own in-plane tensile stress to counteract the mutual attraction force.

[0085] When the high-tensile-stress film 6 is subjected to a sufficiently large external force and comes into contact with and adheres to the periodic support structure of the sacrificial layer material 3, the high-tensile-stress film 6 requires an even greater external force to continue contacting the metallization layer 2 due to the effect of the periodic support structure. According to Hooke's Law, the deformation per unit size of the elastic membrane is approximately linearly related to the force per unit area. Therefore, under the same external force, the ratio of the downward deformation of the high-tensile-stress film 6 with the periodic support structure to that without the periodic support structure is: Therefore, devices with periodic support structures can resist stronger external forces.

[0086] Therefore, the periodic support structure retained by the sacrificial layer material 3 can greatly reduce the mutual attraction between the top high-tension film 6 and the bottom structure, and can also greatly reduce the downward deformation of the high-tension film when subjected to the same external force, thereby preventing the high-tension film 6 from being adsorbed by the bottom sacrificial layer material 3 and metallization layer 2.

[0087] The technical solution of this application will be further described below with reference to specific embodiments.

[0088] Example 1

[0089] A 500μm thick high-resistivity silicon wafer was selected as the substrate. The first metallization layer was 50nm thick niobium, the first sacrificial layer was 100nm thick amorphous silicon, and the second sacrificial layer was 300nm thick silicon dioxide. The high-tensile stress film was 100nm thick silicon nitride, and the second metallization layer was 100nm thick niobium. The total size of the periodic release window was a side length L. tot =500μm, the arrangement interval period in both directions is L xy =10μm, the area of ​​the middle part of metallization layer 6 is S=4500μm. 2 The width L of each supporting structure retained by the first sacrificial layer material left =0.5μm.

[0090] A thin-film mechanical oscillator with an anti-adsorption structure was prepared according to the preparation method of this application:

[0091] The first metallization layer is grown on the upper surface of the substrate using micro / nano fabrication processes such as sputtering or evaporation.

[0092] Using PECVD technology, a first sacrificial layer is prepared by growing on the surface of the first metallized layer, and a second sacrificial layer is prepared by growing on the surface of the first sacrificial layer.

[0093] A portion of the second sacrificial layer, a portion of the first sacrificial layer, and the first metallization layer are patterned and removed using photolithography and dry etching processes, exposing a portion of the surface of the substrate.

[0094] High-tensile-stress thin films were prepared by growing the entire device surface using LPCVD technology.

[0095] A portion of the high-tension film, a portion of the second sacrificial layer, and a portion of the first sacrificial layer are patterned and removed using photolithography and dry etching processes, exposing a portion of the surface of the first metallization layer.

[0096] A second metallization layer is grown on the entire device surface using evaporation or sputtering processes.

[0097] A portion of the second metallization layer is patterned and removed using photolithography and dry etching processes to define its structure.

[0098] Photolithography and dry etching processes are used to pattern and remove part of the high-tension stress film and the second sacrificial layer, forming periodically distributed sacrificial layer release windows;

[0099] The wet etching process using KOH aqueous solution removes most of the first sacrificial layer through periodically distributed sacrificial layer release windows. When the first sacrificial layer at the bottom of the periodically distributed sacrificial layer release window still has a support structure with a width of about 500 nm, the wet etching process is stopped.

[0100] The BOE solution wet etching process is used to remove the second sacrificial layer by etching through periodically distributed sacrificial layer release windows, so that the high-tensile stress film forms a suspended film, which constitutes a thin film mechanical oscillator.

[0101] Example 2

[0102] The preparation steps are the same as in Example 1.

[0103] 300μm sapphire was selected as the substrate. The first metallization layer was 50nm thick aluminum, the first sacrificial layer was 50nm thick amorphous silicon, and the second sacrificial layer was 500nm thick silicon dioxide. The high-tensile stress film was 50nm thick silicon nitride, and the second metallization layer was 50nm thick aluminum. The total size of the periodic release window was L. tot =500μm, the arrangement interval period in both directions is L xy =10μm, the area of ​​the middle part of metallization layer 6 is S=4500μm. 2 The width L of each supporting structure retained by the first sacrificial layer material left=0.5μm.

[0104] Comparative Example

[0105] The preparation steps are basically the same as in Example 1, except that: the first sacrificial layer material and the KOH etching step of the first sacrificial layer material in Example 1 are not included. Instead, the second sacrificial layer material is directly and completely etched with BOE solution to form a suspended thin film mechanical oscillator.

[0106] Experimental Example

[0107] The automatic anti-adhesion function of the thin-film mechanical oscillator of Example 1 and the comparative example of this application was tested as follows:

[0108] Alcohol was dropped onto the surface of the mechanical oscillator in Example 1, so that the originally suspended mechanical oscillator film was completely immersed in the alcohol. Figure 4 As shown in (a), as the alcohol gradually evaporates, due to the surface tension of the liquid, the suspended mechanical oscillator film will be temporarily adsorbed onto the first metallization layer at the bottom, as... Figure 4 (b) As shown in the upper left corner; when the alcohol completely evaporates, due to the presence of the periodic support structure formed by the first sacrificial layer material, the high-tensile-stress film will be stretched upwards around each support structure due to its own high in-plane tensile stress, thus detaching from the bottom first metallization layer, as shown. Figure 4 (c) As shown in the upper left corner; finally, the entire mechanical oscillator film returns to a completely suspended state, as shown. Figure 4 As shown in (d).

[0109] like Figure 5 As shown, after the thin-film mechanical oscillator device prepared in the comparative example was taken out of the solution and allowed to dry naturally, the mechanical oscillator film was adsorbed onto the first metal layer due to the surface tension of the liquid and could not be restored to its suspended state.

[0110] In summary, the thin-film mechanical oscillator of this application can automatically prevent the suspended thin-film mechanical oscillator in the device from being adsorbed by the bottom microwave-controlled readout structure by utilizing this columnar structure. Furthermore, it can automatically prevent thin-film adsorption problems caused by external vibrations or electrostatic attraction after sample preparation.

[0111] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of this application. It should be noted that those skilled in the art can make several improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. A thin-film mechanical oscillator with an anti-adsorption structure, characterized in that, include: Substrate; A first metallization layer is grown on one side of the substrate. The first sacrificial layer is grown on the first metallization layer and is a periodically arranged columnar structure; The second sacrificial layer grows on the first sacrificial layer and serves as a support structure located at the edge of the first sacrificial layer; A high-stress thin film layer is grown on the second sacrificial layer. The high-stress thin film layer has a suspended thin film region and a non-suspended thin film region. There is a cavity between the high-stress thin film layer and the substrate that allows the suspended thin film region to be suspended. The periodically arranged columnar structure is located in the region of the cavity; the non-suspended thin film region is supported by the first sacrificial layer and the second sacrificial layer; The second metallization layer is grown on the high-tensile-stress thin film layer and is located at the center of the suspended thin film region and the non-suspended thin film region.

2. The thin-film mechanical oscillator with an anti-adsorption structure according to claim 1, characterized in that, The first sacrificial layer and the second sacrificial layer are made of different materials; The materials of the first sacrificial layer and the second sacrificial layer are selected from amorphous silicon or silicon dioxide.

3. The thin-film mechanical oscillator with an anti-adsorption structure according to claim 1 or 2, characterized in that, The thickness of the first sacrificial layer is 20-100 nm; The thickness of the second sacrificial layer is 100-500 nm.

4. The thin-film mechanical oscillator with an anti-adsorption structure according to claim 3, characterized in that, The thickness of the substrate is 200-500 μm; The thickness of the first metallization layer is 50-200 nm; The thickness of the second metallization layer is 50-200 nm; The thickness of the high-tensile stress thin film layer is 50-100 nm.

5. The thin-film mechanical oscillator with an anti-adsorption structure according to claim 1, characterized in that, Each of the periodically arranged columnar structures has a width of 200-1000 nm, and the period interval is 5-20 μm.

6. The thin-film mechanical oscillator with an anti-adsorption structure according to claim 4 or 5, characterized in that, The substrate includes: a high-resistivity silicon substrate or a sapphire substrate; The materials of the first metallization layer and the second metallization layer include niobium or aluminum; The material of the high-tensile-stress thin film layer includes silicon nitride or silicon carbide.

7. A method for preparing a thin-film mechanical oscillator with an anti-adsorption structure, characterized in that, include: A first metallization layer is grown on the surface of a substrate. A first sacrificial layer and a second sacrificial layer are sequentially grown on the surface of the first metallization layer; Patterned etching removes the edge regions of the first metallization layer, the first sacrificial layer, and the second sacrificial layer, exposing the edge of the substrate. A high-tensile-stress thin film layer is grown on the surface of the second sacrificial layer and at the edge of the substrate. Patterned etching removes portions of the first sacrificial layer, the second sacrificial layer, and the high-tensile-stress thin film layer, exposing portions of the first metallization layer; A second metallization layer is grown on the surface of the high-tensile-stress thin film layer and on the surface of the exposed first metallization layer; The second metallization layer is etched to obtain the pattern of the second metallization layer; The second sacrificial layer and the high-tensile stress thin film layer are patterned and etched to obtain periodically arranged release windows, which are circular with a diameter of 2-8 μm and a period of 5-20 μm. Part of the first sacrificial layer is removed by etching through the release window and the first wet etching solution to obtain a periodically arranged columnar structure; By etching away part of the second sacrificial layer through the release window and the second wet etching solution, a support structure and cavity are obtained at the edge of the first sacrificial layer, so that the high-tensile stress thin film layer forms a suspended thin film region and a non-suspended thin film region, resulting in a thin film mechanical oscillator with an anti-adsorption structure.

8. The method for preparing a thin-film mechanical oscillator with an anti-adsorption structure according to claim 7, characterized in that, The first sacrificial layer and the second sacrificial layer are made of different materials; The materials of the first sacrificial layer and the second sacrificial layer are selected from amorphous silicon or silicon dioxide.

9. The method for preparing a thin-film mechanical oscillator with an anti-adsorption structure according to claim 8, characterized in that, The thickness of the first sacrificial layer is 20-100 nm; The thickness of the second sacrificial layer is 100-500 nm; The thickness of the substrate is 200-500 μm; The thickness of the first metallization layer is 50-200 nm; The thickness of the second metallization layer is 50-200 nm; The thickness of the high-tensile-stress thin film layer is 50-100 nm; Each of the periodically arranged columnar structures has a width of 200-1000 nm, and the period interval is 5-20 μm.

10. The method for preparing a thin-film mechanical oscillator with an anti-adsorption structure according to claim 9, characterized in that, The substrate includes: a high-resistivity silicon substrate or a sapphire substrate; The materials of the first metallization layer and the second metallization layer include niobium or aluminum; The material of the high-tensile-stress thin film layer includes silicon nitride or silicon carbide.

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