Method for adjusting steady-state pipe diameter of self-crimping inductor
By changing the shape of the metal conductive layer in the self-curling inductor and using photolithography etching, the problem of steady-state diameter control of the self-curling inductor was solved, achieving precise adjustment and performance improvement. This method is suitable for steady-state diameter control of self-curling inductors in the field of communication technology.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-16
- Publication Date
- 2026-03-24
AI Technical Summary
Existing self-winding inductors have limited steady-state diameter control methods, are difficult to control, and have low accuracy, which affects device performance optimization and application.
By changing the shape of the metal conductive layer, a mask cutout pattern with continuously or quasi-continuously increasing width is formed in the self-rolling inductor using photolithography and etching processes. Combined with the deposition and etching of the germanium sacrificial layer, silicon nitride stress layer and aluminum oxide protective layer, the steady-state diameter of the self-rolling inductor can be precisely adjusted.
It enables precise adjustment of the steady-state diameter of the self-winding inductor, improves the overall performance of the inductor, provides greater design flexibility and production efficiency, reduces costs, and ensures the stability and reliability of the inductor performance.
Smart Images
Figure CN121726221A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of communication technology, and in particular to a method for adjusting the steady-state diameter of a self-curling inductor. Background Technology
[0002] Inductors are a crucial component of integrated circuits, and self-curling inductors are a novel alternative to traditional inductors. Their principle involves the spontaneous curling of a two-dimensional structure into a three-dimensional solenoid through the stress difference between the inside and outside of a thin film. This represents a preliminary transformation from planar inductors to three-dimensional inductors, enabling the miniaturization and integration of passive inductor-like devices. It significantly increases inductance and space utilization, and greatly improves the quality factor and self-resonant frequency.
[0003] Despite the promising prospects of 3D self-rolling technology, it still faces many challenges in its development, especially in its practical application and industrialization. For example, balancing the performance and size of self-rolling inductors is a major challenge. While the 3D self-rolling structure can theoretically significantly reduce the footprint, without precise control of its geometric parameters, it is difficult to achieve the optimal balance between key performance indicators such as quality factor and self-resonant frequency in its steady-state diameter. Furthermore, the inter-turn gap affects parasitic capacitance, which in turn affects the self-resonant frequency, and the diameter affects the inductance and Q value; without precise control, this limits the optimization and application of device performance. Currently, parameter control of self-rolling inductors can only be achieved by changing the film thickness or material, a limited approach that significantly restricts the upper limit of device performance optimization.
[0004] In view of this, the present invention provides a method for adjusting the steady-state diameter of a self-curling inductor to solve the above problems. Summary of the Invention
[0005] The purpose of this invention is to provide a method for adjusting the steady-state diameter of a self-curling inductor.
[0006] To solve the above technical problems, the present invention provides a method for adjusting the steady-state diameter of a self-curling inductor, characterized in that the adjustment method includes:
[0007] Step 1, Clean the substrate; Select a silicon substrate and rinse it with acetone solution and isopropanol solution in sequence, then rinse it with deionized water, and finally blow the surface of the substrate with high-purity, dry nitrogen gas.
[0008] Step 2, Deposit germanium sacrificial layer; Use a vacuum deposition machine to deposit a germanium sacrificial layer on a cleaned substrate.
[0009] Step 3, deposit dual-frequency silicon nitride; using PECVD plasma-enhanced chemical vapor deposition, first deposit a lower stress layer on the germanium sacrificial layer, and then deposit an upper stress layer.
[0010] Step 4: First photolithography step to determine the mesa;
[0011] Step 5: Deposit an alumina protective layer using the ALD atomic layer deposition method;
[0012] Step 6: Second photolithography deposition of the conductive metal layer;
[0013] Step 6.1, Second coating, exposure, and development: Spin-coating a phase-negative photoresist onto the surface of the alumina protective layer, aligning and exposing the image using a photomask, and developing the image to obtain the upper liquid negative photoresist layer, which has a hollow pattern with a continuous or quasi-continuously increasing width.
[0014] Step 7: The third photolithography step determines the etching window;
[0015] Step 8: Prepare a self-rolling inductor with a metallic structure.
[0016] As a further improvement of the present invention, in step 2, the thickness of the germanium sacrificial layer is 50-100 nm.
[0017] As a further improvement of the present invention, step 4 includes:
[0018] Step 4.1: First application of adhesive, exposure, and development.
[0019] HMDS hexamethylsilane is spin-coated onto the surface of the lower stress layer to form a film, followed by spin-coating of liquid positive photoresist; the photoresist portion to be retained is blocked using a photolithography machine, and the mesa pattern on the first mask is transferred to the surface of the upper stress layer, and the positive photoresist layer is obtained by exposure and development, the positive photoresist layer comprising positive photoresist blocks.
[0020] Step 4.2, Reactive Ion Etching (RIE)
[0021] Using a reactive ion etching (RIE) device, the germanium sacrificial layer, upper stress layer, and lower stress layer exposed around the positive photoresist block are etched away, and a shallow layer is etched downwards onto the substrate.
[0022] Step 4.3, Remove the liquid phase positive photoresist.
[0023] Remove the positive photoresist block, and retain the germanium sacrificial layer, upper stress layer and lower stress layer at the bottom of the positive photoresist block to obtain a mesa.
[0024] As a further improvement of the present invention, in step 5, an aluminum oxide protective layer is deposited on the lower stress layer using ALD atomic layer deposition. The thickness of the aluminum oxide protective layer is 18 nm ± 0.1 nm to prevent other thin films from being accidentally etched in subsequent processes.
[0025] As a further improvement of the present invention, step 6 also includes:
[0026] Step 6.2, depositing a metal conductive layer: based on step 6.1, a copper conductive layer is vacuum deposited using an electron beam evaporation device;
[0027] Step 6.3: Prepare a substrate with a metal pattern, and completely remove the liquid negative photoresist layer with a resist remover. At this time, the metal conductive layer on the liquid negative photoresist layer is also removed to obtain a copper conductive layer with a continuous or quasi-continuously increasing planar pattern.
[0028] In step 6.1, the liquid negative photoresist layer is configured with a second mask cutout pattern having a width that is continuously or quasi-continuously increasing.
[0029] As a further improvement of the present invention, step 7 includes:
[0030] Step 7.1, third coating, exposure, and development: spin coating liquid negative photoresist onto the copper conductive layer, using a contact lithography machine, and exposing and developing the third mask to obtain the etching window. At this time, only the liquid negative photoresist is removed from the etching window.
[0031] Step 7.2, RIE (Reactive Ion Etching): Using reactive ion etching (RIE), the aluminum oxide protective layer, upper stress layer, and lower stress layer corresponding to the area below the etching window are etched vertically downwards to obtain the etching window.
[0032] Step 7.3: Remove the liquid phase positive photoresist, remove the positive photoresist block, and retain the germanium sacrificial layer, upper stress layer and lower stress layer at the bottom of the positive photoresist block.
[0033] As a further improvement of the present invention, in step 8, the substrate obtained in step 7 is placed into a xenon fluoride etching machine, so that xenon difluoride enters the etching window to selectively etch the germanium sacrificial layer, so as to cause stress mismatch in the strain layer. The upper stress layer is configured as a low-frequency silicon nitride thin film, and the lower stress layer is configured as a high-frequency silicon nitride thin film. The planar thin film spontaneously curls to obtain a micro-nanotube-shaped self-curling inductor.
[0034] As a further improvement of the present invention, the faster the width increase rate of the second mask cutout pattern with continuously or quasi-continuously increasing width, the smaller the steady-state diameter of the self-curling inductor.
[0035] As a further improvement of the present invention, the second mask cutout pattern with continuously or quasi-continuously increasing width is configured as a trapezoid, triangle, parabola, or semicircle.
[0036] As a further improvement of the present invention, the lower stress layer is configured as a tensile layer with a thickness ranging from 20 to 40 nm; the upper stress layer is configured as a compression layer with a thickness ranging from 20 to 40 nm.
[0037] This invention provides a method for adjusting the steady-state diameter of a self-curling inductor, comprising cleaning the substrate, depositing a germanium sacrificial layer, depositing a dual-frequency silicon nitride stress layer, and depositing an alumina protective layer. The first photolithography and reactive ion etching define the mesa structure; the second photolithography forms the metal conductive layer; and the third photolithography and reactive ion etching define the etching window. In the second photolithography step of forming the metal conductive layer, HMDS and negative photoresist are spin-coated onto the surface of the high-frequency silicon nitride stress layer of the unit substrate. A second mask with a continuously or quasi-continuously increasing planar pattern (i.e., a cutout pattern) is used for overlay alignment, exposure, and development. Subsequently, an electron beam evaporation device is used to deposit a copper thin film on the entire substrate surface to form the metal conductive layer. Finally, a stripping operation is performed using a resist remover to remove the areas with negative photoresist and the copper film covering them, thereby forming a firmly attached copper conductive layer pattern with a specific cross-sectional shape in the areas without photoresist. Attached Figure Description
[0038] Figure 1 This is a schematic diagram of the structure of the present invention after sequentially depositing a sacrificial layer, a lower stress layer, and an upper stress layer on a substrate of a coiled inductor.
[0039] Figure 2 This is a schematic diagram of the structure formed by depositing an alumina protective layer after the first photolithography step in this invention.
[0040] Figure 3 This is a three-dimensional schematic diagram of the positive trapezoidal structure of the metal conductive layer after deposition and the second photolithography in this invention.
[0041] Figure 4 This is a side view of the inductor after it has been rolled up, where the metal conductive layer of the present invention has a trapezoidal structure.
[0042] Figure 5 This is a three-dimensional view of the inductor after it has been rolled up, where the metal conductive layer of the present invention has a trapezoidal structure.
[0043] The labels in the accompanying drawings are explained as follows:
[0044] Substrate 1, germanium sacrificial layer 2, lower stress layer 3, upper stress layer 4, aluminum oxide protective layer 5, and metal conductive layer 6. Detailed Implementation
[0045] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, further illustrates the method for adjusting the steady-state diameter of a self-curling inductor proposed in this invention. It should be noted that the drawings are all in a very simplified form and use non-precise scales, intended only to facilitate and clarify the illustration of the embodiments of the invention. Furthermore, the structures shown in the drawings are often part of the actual structure. In particular, different figures may emphasize different aspects and sometimes use different scales.
[0046] To address the shortcomings of existing three-dimensional self-curling inductors, such as limited steady-state diameter control methods, high control difficulty, and low accuracy, this invention provides a method for adjusting the steady-state diameter of a self-curling inductor. This method involves changing the shape of the metal conductive layer 6 to adjust the steady-state diameter of the self-curling inductor. This method is simple to implement, provides precise control, and can effectively improve the overall performance of the self-curling inductor.
[0047] This invention provides a method for adjusting the steady-state diameter of a self-curling inductor, the method comprising:
[0048] Step 1, Cleaning substrate 1; Select substrate 1 made of silicon, rinse substrate 1 with acetone solution and isopropanol solution in sequence, then rinse with deionized water, and finally blow dry the surface of substrate 1 with high-purity, dry nitrogen gas.
[0049] Step 2, deposit germanium sacrificial layer 2; using a vacuum deposition machine, deposit germanium sacrificial layer 2 on the cleaned substrate 1;
[0050] Step 3, deposit dual-frequency silicon nitride; using PECVD plasma-enhanced chemical vapor deposition, first deposit a lower stress layer 3 on the germanium sacrificial layer 2, and then deposit an upper stress layer 4.
[0051] Step 4: First photolithography step to determine the mesa;
[0052] Step 5: Deposit an alumina protective layer 5 using the ALD atomic layer deposition method;
[0053] Step 6: Second photolithography deposition of the conductive metal layer 6;
[0054] Step 6.1, Second coating, exposure, and development: Spin-coating a phase-negative photoresist onto the surface of the alumina protective layer 5, aligning and exposing using a mask, and developing to obtain an upper liquid negative photoresist layer with a continuously or quasi-continuously increasing width cutout pattern; the liquid negative photoresist layer is configured with a second mask cutout pattern with continuously or quasi-continuously increasing width; Step 7, Third photolithography to determine the etching window; Step 8, Fabrication of a metal structure self-curling inductor.
[0055] In other words, the self-curling inductor of the present invention includes a substrate 1 and a self-curling tubular structure. The self-curling tubular structure is a multilayer thin film consisting of a lower stress layer 3, an upper stress layer 4, an aluminum oxide protective layer 5, and a metal conductive layer 6 arranged sequentially from the outside to the inside. After being released, the multilayer thin film curls inward multiple times along a preset conductive pattern to form a tubular three-dimensional structure.
[0056] This configuration allows for adjustment of the steady-state diameter of the self-rolling inductor by changing the shape of the conductive metal layer 6—specifically, by using a mask pattern with continuously or quasi-continuously increasing width. This adjustment method is not only simple to implement but also highly precise, significantly improving the overall performance of the self-rolling inductor. Specifically, as the rate of increase in the width of the mask pattern accelerates, the steady-state diameter of the self-rolling inductor decreases accordingly. This relationship provides greater flexibility for inductor design and optimization.
[0057] Furthermore, by selecting different shaped mask patterns, such as trapezoids, triangles, parabolas, or semicircles, the diameter variation forms of the self-curling inductor can be further enriched to meet the performance requirements of different application scenarios. Simultaneously, precise control of the thickness of the lower stress layer 3 and the upper stress layer 4 is also a key factor in achieving precise steady-state diameter adjustment of the self-curling inductor. Through these measures, this invention successfully solves the problems of limited forms, high difficulty in control, and low accuracy in steady-state diameter adjustment of existing three-dimensional self-curling inductors, laying a solid foundation for the application and promotion of self-curling inductors.
[0058] Furthermore, in step 2, the thickness of the germanium sacrificial layer 2 is 50–100 nm. Using germanium as a sacrificial layer allows for selective etching with xenon fluoride, and the germanium film has a smooth, dense surface, providing an ideal platform for depositing the stress layer and the metallic conductive layer 6.
[0059] Step 4 includes: Step 4.1, first coating, exposure, and development: HMDS (hexamethylsilane) is spin-coated onto the surface of the lower stress layer 3 for film formation. Here, HMDS enhances the adhesion of the photoresist. Then, liquid positive photoresist is spin-coated. The photoresist portions to be retained are blocked using a photolithography machine, and the mesa pattern on the first mask is transferred to the surface of the upper stress layer 4. Exposure and development are performed to obtain a positive photoresist layer. The positive photoresist layer includes positive photoresist blocks, which are spaced and uniformly distributed square photoresist blocks, i.e., the transferred mesa pattern. Step 4.2, RIE (Reactive Ion Etching): Using a reactive ion etching (RIE) device, the germanium sacrificial layer 2, upper stress layer 4, and lower stress layer 3 exposed around the positive photoresist blocks are etched away, and a shallow layer is etched downwards onto the substrate 1. Step 4.3, Remove liquid phase positive photoresist: Remove the positive photoresist block, retaining the germanium sacrificial layer 2, upper stress layer 4 and lower stress layer 3 at the bottom of the positive photoresist block to obtain a mesa.
[0060] This setup ensures accurate transfer of the mesa pattern during the first photolithography process by controlling the parameters of resist coating, exposure, and development, laying the foundation for subsequent process steps. The RIE (Reactive Ion Etching) step utilizes a high-energy ion beam to selectively etch specific materials, achieving fine processing of the multilayer thin film structure and ensuring precise formation of the mesa structure. Finally, the removal of the liquid-phase positive photoresist not only cleans the surface but also preserves key structural layers, creating conditions for subsequent deposition of the metal conductive layer 6 and the formation of the self-curling inductor structure. Further, in step 5, an alumina protective layer 5 with a thickness of 18 nm ± 0.1 nm is deposited on the lower stress layer 3 using ALD (Atomic Layer Deposition) to prevent accidental etching of other thin films in subsequent processes.
[0061] Step 6 further includes: Step 6.2, depositing a metal conductive layer 6, using an electron beam evaporation device to vacuum deposit a copper conductive layer based on the step 6.1; preferably, the thickness of the copper conductive layer is 80-300 nm. This method can deposit a copper mold with extremely high purity and good density, improving the quality factor of the inductor. Step 6.3, preparing a substrate with a metal pattern, completely removing the liquid negative photoresist layer with a resist remover, at which time the metal conductive layer 6 located on the liquid negative photoresist layer is also removed, to obtain a copper conductive layer with a continuously or quasi-continuously increasing planar pattern.
[0062] Step 7 includes: Step 7.1, third coating, exposure, and development: liquid negative photoresist is spin-coated onto the copper conductive layer, and an etching window is obtained by exposure and development using a contact lithography machine with a third mask. At this time, only the liquid negative photoresist is removed from the etching window; Step 7.2, reactive ion etching (RIE): using reactive ion etching (RIE), the aluminum oxide protective layer 5, upper stress layer 4, and lower stress layer 3 below the etching window are vertically etched downwards to obtain the etching window; Step 7.3, removal of liquid positive photoresist: the positive photoresist block is removed, while the germanium sacrificial layer 2, upper stress layer 4, and lower stress layer 3 below the positive photoresist block are retained.
[0063] In step 8, the substrate obtained in step 7 is placed in a xenon fluoride etching machine, allowing xenon difluoride to selectively etch the germanium sacrificial layer 2 through the etching window, thereby causing stress mismatch in the strain layer. The upper stress layer 4 is configured as a low-frequency silicon nitride thin film, and the lower stress layer 3 is configured as a high-frequency silicon nitride thin film. The planar thin film spontaneously curls to obtain a micro / nanotube-shaped self-curling inductor. Preferably, the lower stress layer 3 is configured as a stretching layer with a thickness ranging from 20 to 40 nm; the upper stress layer 4 is configured as a compression layer with a thickness ranging from 20 to 40 nm.
[0064] In this invention, the faster the width increase rate of the second mask cutout pattern with continuously or quasi-continuously increasing width, the smaller the steady-state diameter of the self-curling inductor. The second mask cutout pattern with continuously or quasi-continuously increasing width is configured as a trapezoid, triangle, parabola, or semicircle. That is, a planar pattern with continuously or quasi-continuously increasing width is designed in a predetermined curling direction. The width increase rate of the planar pattern, i.e., the hypotenuse angle of the trapezoid or the derivative of the curve, is related to the final steady-state diameter; the faster the increase, the greater the gradient, the tighter the curl, and the smaller the diameter.
[0065] In the process step of forming the metal conductive layer 6, the adjustment method of the present invention controls the final planar shape of the metal conductive layer 6 through photolithography. The planar pattern or shape of the present invention can be configured as a trapezoid, triangle, parabola, or semicircle, etc. The planar pattern only needs to satisfy the requirement of continuous or quasi-continuous width increase; no further restrictions are imposed. The metal conductive layer 6 of the present invention can reduce the final steady-state diameter of the self-curling inductor. Compared with the traditional fully covered structure, more curling turns can be obtained in a planar structure of the same length, thereby helping to improve the inductance value. Furthermore, a smaller curl curvature means that the material experiences less stress when bent, thus significantly enhancing the mechanical stability and reliability of the entire inductor structure. In practical applications, this adjustment method exhibits extremely high flexibility and adaptability. By adjusting the width increment rate and shape of the second mask cutout pattern, the steady-state diameter of the self-curling inductor can be precisely controlled to meet the inductance parameter requirements of different circuit designs. For example, in high-frequency circuits, smaller diameter self-curled inductors are needed to reduce parasitic capacitance and increase the self-resonant frequency; while in low-frequency circuits, larger diameter inductors may be required to obtain higher inductance values. The adjustment method of this invention easily meets these requirements, providing more options for circuit design. Simultaneously, the adjustment method of this invention also has the advantages of simple process and low cost. It does not require complex equipment or expensive materials, and can be achieved through conventional photolithography and etching processes. This not only reduces production costs but also improves production efficiency, making large-scale production and application of self-curled inductors possible. Furthermore, the adjustment method of this invention has good repeatability and stability. Due to the precision of the photolithography and etching processes, the steady-state diameter of the self-curled inductor prepared each time remains highly consistent, thereby ensuring the stability and reliability of the inductor performance. This is particularly important for applications requiring high-precision inductors.
[0066] In summary, the method for adjusting the steady-state diameter of a self-curling inductor according to the present invention includes cleaning the substrate 1, depositing a germanium sacrificial layer 2, depositing a dual-frequency silicon nitride stress layer, and depositing an alumina protective layer 5. The first photolithography and reactive ion etching define the mesa structure, the second photolithography forms the metal conductive layer 6, and the third photolithography and reactive ion etching define the etching window. In the second photolithography step of forming the metal conductive layer 6, HMDS and negative photoresist are spin-coated onto the surface of the high-frequency silicon nitride stress layer of the unit substrate. A second mask with a continuously or quasi-continuously increasing planar pattern (i.e., a cutout pattern) is used for overlay alignment, exposure, and development. Subsequently, an electron beam evaporation device is used to deposit a copper thin film on the entire substrate surface to form the metal conductive layer 6. Finally, a stripping operation is performed using a resist remover to remove the areas with negative photoresist and the copper film covering them, thereby forming a firmly attached copper conductive layer pattern with a specific cross-sectional shape in the areas without photoresist.
[0067] This invention's adjustment method overcomes the limitations of traditional methods that merely change the material used to alter stress or adjust thickness to control the curling gap and tube diameter. By designing a two-dimensional planar pattern of the pre-formed structural layer—a planar pattern with continuously or quasi-continuously increasing width—it achieves control over the steady-state tube diameter of the self-curled three-dimensional inductor. This method shifts performance control from the complex material processing level to the flexible pattern design level, overcoming the difficulty of precisely controlling geometric parameters in existing technologies. This invention's adjustment method makes the steady-state tube diameter of the self-curled inductor a pre-designable variable. Researchers only need to change the design of the photolithography mask to fabricate inductors that meet different circuit specifications under the same process conditions, greatly improving design flexibility and development efficiency while reducing R&D costs. Preferably, the self-curled inductor with the trapezoidal metal conductive layer 6 exhibits a smaller steady-state tube diameter and more curling turns, directly contributing to a higher inductance value; simultaneously, the increased curling gap effectively reduces parasitic capacitance between adjacent conductors, while the gentler curvature significantly reduces bending stress in the material, greatly enhancing the mechanical stability and reliability of the device during long-term use. Furthermore, the process system employed, such as the germanium sacrificial layer 2, the alumina protective layer 5, and the copper conductive layer, is compatible with traditional processes. The germanium sacrificial layer 2 has a fast etching rate and causes minimal damage to the upper structure; the alumina protective layer 5 effectively ensures the structural integrity during the process; and the copper conductive layer deposited by electron beam evaporation has high purity and good conductivity, which is beneficial for improving the optimal quality factor (Q value) of the inductor.
[0068] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to mutually. In addition, different parts between embodiments can also be combined with each other, and this invention does not limit this.
[0069] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.
Claims
1. A method of adjusting the steady state tube diameter of a self-curl inductor, comprising: The adjustment method includes: Step 1, Clean the substrate; Select a silicon substrate and rinse it with acetone solution and isopropanol solution in sequence, then rinse it with deionized water, and finally blow the surface of the substrate with high-purity, dry nitrogen gas. Step 2, Deposit germanium sacrificial layer; Use a vacuum deposition machine to deposit a germanium sacrificial layer on a cleaned substrate. Step 3, deposit dual-frequency silicon nitride; using PECVD plasma-enhanced chemical vapor deposition, first deposit a lower stress layer on the germanium sacrificial layer, and then deposit an upper stress layer. Step 4: First photolithography step to determine the mesa; Step 5: Deposit an alumina protective layer using the ALD atomic layer deposition method; Step 6: Second photolithography deposition of the conductive metal layer; Step 6.1, Second coating, exposure, and development: Spin-coating a phase-negative photoresist onto the surface of the alumina protective layer, aligning and exposing the image using a photomask, and developing the image to obtain the upper liquid negative photoresist layer, which has a hollow pattern with a continuous or quasi-continuously increasing width. Step 7: The third photolithography step determines the etching window; Step 8: Prepare a self-rolling inductor with a metallic structure.
2. The method of adjusting the self-curling inductance steady state tube diameter according to claim 1, characterized in that: In step 2, the thickness of the germanium sacrificial layer is 50–100 nm.
3. The method of adjusting the self-curling inductance steady state tube diameter of claim 1, wherein, Step 4 includes: Step 4.1: First application of adhesive, exposure, and development. HMDS hexamethylsilane is spin-coated onto the surface of the lower stress layer to form a film, followed by spin-coating of liquid positive photoresist; the photoresist portion to be retained is blocked using a photolithography machine, and the mesa pattern on the first mask is transferred to the surface of the upper stress layer, and the positive photoresist layer is obtained by exposure and development, the positive photoresist layer comprising positive photoresist blocks. Step 4.2, Reactive Ion Etching (RIE) Using a reactive ion etching (RIE) device, the germanium sacrificial layer, upper stress layer, and lower stress layer exposed around the positive photoresist block are etched away, and a shallow layer is etched downwards onto the substrate. Step 4.3, Remove the liquid phase positive photoresist. Remove the positive photoresist block, and retain the germanium sacrificial layer, upper stress layer and lower stress layer at the bottom of the positive photoresist block to obtain a mesa.
4. The method of adjusting the self-curling inductance steady state tube diameter of claim 1, wherein: In step 5, an aluminum oxide protective layer is deposited on the lower stress layer using ALD atomic layer deposition. The thickness of the aluminum oxide protective layer is 18 nm ± 0.1 nm to prevent other thin films from being accidentally etched in subsequent processes.
5. The method of adjusting the self-curling inductance steady state tube diameter of claim 1, wherein, Step 6 also includes: Step 6.2, depositing a metal conductive layer: based on step 6.1, a copper conductive layer is vacuum deposited using an electron beam evaporation device; Step 6.3: Prepare a substrate with a metal pattern, and completely remove the liquid negative photoresist layer with a resist remover. At this time, the metal conductive layer on the liquid negative photoresist layer is also removed to obtain a copper conductive layer with a continuous or quasi-continuously increasing planar pattern. In step 6.1, the liquid negative photoresist layer is configured with a second mask cutout pattern having a width that is continuously or quasi-continuously increasing.
6. The method of adjusting the self-curling inductance steady state tube diameter of claim 1, wherein, Step 7 includes: Step 7.1, third coating, exposure, and development: spin coating liquid negative photoresist onto the copper conductive layer, using a contact lithography machine, and exposing and developing the third mask to obtain the etching window. At this time, only the liquid negative photoresist is removed from the etching window. Step 7.2, RIE (Reactive Ion Etching): Using reactive ion etching (RIE), the aluminum oxide protective layer, upper stress layer, and lower stress layer corresponding to the area below the etching window are etched vertically downwards to obtain the etching window. Step 7.3: Remove the liquid phase positive photoresist, remove the positive photoresist block, and retain the germanium sacrificial layer, upper stress layer and lower stress layer at the bottom of the positive photoresist block.
7. The method of adjusting the self-curling inductive steady state tube diameter of claim 1, wherein: In step 8, the substrate obtained in step 7 is placed into a xenon fluoride etching machine, so that xenon difluoride enters the etching window to selectively etch the germanium sacrificial layer, so as to cause stress mismatch in the strain layer. The upper stress layer is configured as a low-frequency silicon nitride thin film, and the lower stress layer is configured as a high-frequency silicon nitride thin film. Planar thin films spontaneously curl up to obtain micro- and nanotube-shaped self-curling inductors.
8. The method of adjusting the self-curling inductive steady state tube diameter of claim 1, wherein: The faster the width of the second mask cutout pattern increases (either continuously or quasi-continuously), the smaller the steady-state diameter of the self-curling inductor.
9. The method of adjusting the self-curling inductive steady state tube diameter of claim 1, wherein: The second mask cutout pattern, with its width continuously or quasi-continuously increasing, is configured as a trapezoid, triangle, parabola, or semicircle.
10. The method for adjusting the steady-state diameter of a self-curling inductor according to claim 1, characterized in that: The lower stress layer is configured as a tensile layer with a thickness ranging from 20 to 40 nm; the upper stress layer is configured as a compression layer with a thickness ranging from 20 to 40 nm.