High-precision inductor based on magnetron sputtering and forming method

Abstract

The invention relates to the technical field of electronics, and discloses a high-precision inductor based on magnetron sputtering and a forming method.The high-precision inductor comprises a thin film deposited on a substrate, the substrate is a carbonyl material or iron silicon chromium, the surface of the substrate is covered with an insulating layer, and the thickness of the insulating layer ranges from 10 nm to 50 nm; the thin film is composed of at least two metal elements, and the thickness of the thin film ranges from 50 nm to 200 nm. The soldering tin layer is deposited on the surface of the thin film and comprises tin or silver, and the thickness of the soldering tin layer ranges from 1 micrometer to 3 micrometers; the magnetic conductivity of the thin film is optimized through material components and a microstructure, so that the inductor has eddy current loss lower than 5% and a Q value higher than 100 in a target frequency range, the thin film is composed of at least two elements of nickel, chromium, copper and vanadium, the magnetic conductivity is optimized, and the adhesive force is enhanced. The material of the inductor is prepared by adopting a magnetron sputtering technology, so that the effect of remarkably improving the conductivity of the inductor is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electronic technology, in particular to a high-precision inductor based on magnetron sputtering and a forming method. BACKGROUND

[0002] With the rapid development of information technology, inductors, as an important component of electronic components, are widely used in communication, computer, automotive electronics and other fields. Especially in high-frequency applications, the performance of inductors directly affects the stability and efficiency of the system. The main function of inductors is to store electrical energy and play a role in filtering, impedance matching and other functions in the circuit. In order to meet the needs of high-frequency signal processing, the design and manufacturing process of inductors are constantly improving, especially in material selection and preparation methods, more and more research focuses on how to optimize the magnetic and conductive properties of inductors to improve their efficiency and stability.

[0003] At present, traditional inductor materials mostly use ferrite, silicon steel and other materials. These materials exhibit large loss and poor conductivity in high-frequency and high-temperature environments, resulting in low working efficiency of inductors, especially in high-speed signal transmission, which is prone to overheating and distortion. In addition, the existing inductor manufacturing method mainly relies on conventional coating or pouring process, although it can meet the general application requirements, but under the requirements of high precision and high frequency, the uniformity and conductivity of the material cannot be fully guaranteed, resulting in insufficient performance of the inductor to meet the strict requirements of modern electronic devices for high frequency and high efficiency.

[0004] In the prior art, the conductive performance of traditional inductor materials is poor, and it is difficult to maintain low resistance and stable performance in high-frequency working environment, especially in high-power and high-frequency working state, inductors are prone to overheating and energy loss. The existing manufacturing process also lacks sufficient precision, resulting in that the uniformity and conductivity of the material cannot be accurately controlled, thereby limiting the effect of inductors in high-frequency applications. SUMMARY

[0005] In view of the deficiencies of the prior art, the present application provides a high-precision inductor based on magnetron sputtering and a forming method, which solves the problems of insufficient conductivity and large high-frequency loss in traditional technology.

[0006] To achieve the above purpose, the present application realizes the following technical scheme: a high-precision inductor based on magnetron sputtering, comprising:

[0007] a thin film deposited on a substrate, the substrate being a carbonyl material or iron-silicon-chromium, the substrate surface being covered with an insulating layer, the insulating layer having a thickness of 10-50 nm;

[0008] The thin film is composed of at least two metal elements, and the thickness of the thin film is 50-200 nm.

[0009] a solder layer deposited on the surface of the thin film, the solder layer comprising tin or silver with a thickness of 1-3 μm;

[0010] The magnetic permeability of the thin film is optimized by material composition and microstructure, so that the inductor has an eddy current loss of less than 5% and a Q value of higher than 100 in a target frequency range.

[0011] Preferably, the thin film is composed of at least two of nickel, chromium, copper and vanadium.

[0012] Preferably, the surface roughness Ra of the solder layer is less than or equal to 2 nm, so as to enhance the soldering quality and reduce the interface resistance.

[0013] A high-precision inductor forming method based on magnetron sputtering, comprising the following steps:

[0014] Step 1: depositing an insulating layer on the surface of a substrate, the insulating layer having a thickness of 10-50 nm;

[0015] Step 2: depositing a thin film on the surface of the substrate by using a magnetron sputtering process, wherein the proportion of metal elements is adjusted according to the high-frequency performance requirements of the inductor;

[0016] Step 3: optimizing the magnetic permeability of the thin film by using the maximum entropy method, and accurately adjusting the thickness of the thin film according to the eddy current loss optimization theory, so as to minimize the eddy current loss;

[0017] Step 4: using an intelligent feedback system to monitor and adjust the sputtering power, substrate temperature and sputtering angle in real time, so as to ensure the uniformity and microstructure optimization of the thin film;

[0018] Step 5: depositing a solder layer on the surface of the thin film by using a magnetron sputtering process, the solder layer and the thin film forming a good bond, and the composition of the solder layer comprising tin or silver.

[0019] Preferably, the eddy current loss of the thin film is reduced by optimizing the thickness of the thin film, the thickness of the thin film being optimized in the working frequency range, and the eddy current loss being proportional to the square of the thickness of the thin film, and the optimal value of the thickness of the thin film being adjusted according to the target of minimizing the eddy current loss.

[0020] Preferably, the sputtering power in the magnetron sputtering process ranges from 300 W to 600 W, and the atmosphere composition is a mixed atmosphere of argon and nitrogen, the proportion of argon to nitrogen being 80:20.

[0021] Preferably, the substrate temperature is controlled between 200°C and 350°C, so as to optimize the microstructure of the thin film and reduce the internal stress of the thin film.

[0022] Preferably, the deposition power of the solder layer is set to 250W to 450W, the thickness of the solder layer is controlled to be between 1μm to 3μm, the atmosphere of the solder layer is controlled to be a mixed atmosphere of argon and oxygen with a ratio of 90%:10%, and the deposition rate of the solder layer is controlled to be between 0.5nm / s to 2nm / s.

[0023] Preferably, the magnetic permeability of the thin film is optimized by the maximum entropy method, and the magnetic permeability is adjusted according to the composition and structure of the thin film during the optimization process.

[0024] Preferably, the high-frequency performance of the inductor is optimized by adjusting the grain size of the thin film and the interface quality between the thin film layers, wherein the grain size is controlled to be between 5nm to 50nm to reduce the magnetic anisotropy and improve the Q value of the inductor.

[0025] The present application provides a high-precision inductor based on magnetron sputtering and a forming method. It has the following advantages:

[0026] 1、The present application uses magnetron sputtering technology to prepare inductor materials, which significantly improves the conductivity of the inductor. Compared with the inductor materials with poor conductivity in the prior art, the present application optimizes the conductivity of the materials by precisely controlling the sputtering process, so that the inductor can significantly reduce the resistance and heat loss during high-frequency operation, ensuring the efficiency and stability of the inductor in high-frequency signal transmission.

[0027] 2、The present application successfully improves the current carrying capacity of the inductor by introducing conductive elements into the inductor material. Compared with the technical solution of traditional inductor materials prone to increased resistance or overheating, the conductive enhancement material of the present application can effectively reduce the loss when current passes through, avoiding excessive temperature caused by excessive current, thereby improving the performance and reliability of the inductor in high-power and high-frequency environments.

[0028] 3、The present application uses an optimized magnetron sputtering process, so that the inductor material not only has excellent magnetic properties, but also achieves an ideal level in conductivity. Compared with the materials in the prior art, the inductor of the present application has lower internal resistance, reducing energy loss in current transmission, thereby significantly improving the efficiency and stability of the inductor under long-time high-frequency operation.

[0029] 4、The inductor material of the present application is precisely optimized in conductivity, achieving the effect of improving the frequency response speed of the inductor and reducing high-frequency loss. Compared with traditional inductor materials, the present application introduces conductive metal elements and controls the conductive path to ensure that the inductor has superior conductivity at high frequencies, greatly improving the stability and efficiency of the inductor in high-speed signal transmission. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 A method flowchart of the present application. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0032] Embodiment:

[0033] The embodiment of the present application provides a high-precision inductor based on magnetron sputtering, comprising:

[0034] A thin film deposited on a substrate, the substrate being a carbonyl material or iron-silicon-chromium, the surface of the substrate being covered with an insulating layer with a thickness of 10-50 nm;

[0035] The thin film is composed of at least two metal elements, and the thickness of the thin film is 50-200 nm;

[0036] A solder layer deposited on the surface of the thin film, the solder layer containing tin or silver, and the thickness of the solder layer being 1-3 microns;

[0037] The magnetic permeability of the thin film is optimized by material composition and microstructure, so that the inductor has an eddy current loss lower than 5% and a Q value higher than 100 in the target frequency range.

[0038] The thin film is composed of at least two elements of nickel, chromium, copper and vanadium, which optimizes the magnetic permeability and enhances the adhesion.

[0039] The surface roughness Ra of the solder layer is ≤2 nm, so as to enhance the soldering quality and reduce the interface resistance.

[0040] Please refer to the accompanying Figure 1 The present application also provides a forming method of a high-precision inductor based on magnetron sputtering, comprising the following steps:

[0041] Step 1: depositing an insulating layer on the surface of the substrate, the thickness of the insulating layer being 10-50 nm;

[0042] Step 2: depositing a thin film on the surface of the substrate by using a magnetron sputtering process, wherein the proportion of metal elements is adjusted according to the high-frequency performance requirements of the inductor;

[0043] Step 3: optimizing the magnetic permeability of the thin film by the maximum entropy method, and accurately adjusting the thickness of the thin film according to the eddy current loss optimization theory, so as to minimize the eddy current loss;

[0044] Step four: Real-time monitoring and adjustment of sputtering power, substrate temperature and sputtering angle are performed by using intelligent feedback system to ensure the uniformity and microstructure optimization of the thin film.

[0045] Step five: A solder layer is deposited on the surface of the thin film by using magnetron sputtering process, forming a good bond between the solder layer and the thin film, and the composition of the solder layer includes tin or silver.

[0046] The eddy current loss of the thin film is reduced by optimizing the thickness of the thin film, the thickness of the thin film is optimized in the working frequency range, and the eddy current loss is proportional to the square of the thickness of the thin film, and the optimal value of the thickness of the thin film is adjusted according to the target of minimizing the eddy current loss.

[0047] The sputtering power in the magnetron sputtering process ranges from 300W to 600W, and the atmosphere composition is a mixture of argon and nitrogen, with a ratio of 80%:20%.

[0048] The substrate temperature is controlled between 200℃ and 350℃ to optimize the microstructure of the thin film and reduce the internal stress of the thin film.

[0049] The deposition power of the solder layer is set to 250W to 450W, the thickness of the solder layer is controlled between 1μm and 3μm, the atmosphere of the solder layer is controlled as a mixture of argon and oxygen, with a ratio of 90%:10%, and the deposition rate of the solder layer is controlled between 0.5nm / s and 2nm / s.

[0050] The permeability of the thin film is optimized by the maximum entropy method, and the permeability is adjusted according to the composition and structure of the thin film during the optimization process.

[0051] The high-frequency performance of the inductor is optimized by adjusting the grain size of the thin film and the interface quality between the thin film layers, and the grain size is controlled between 5nm and 50nm to reduce the magnetic anisotropy and improve the Q value of the inductor.

[0052] As an option, in this embodiment, the substrate can use carbonyl material or iron-silicon-chromium material. Specifically, silicon substrate is suitable for integrated circuit compatible application scenarios, while alumina substrate is more suitable for high temperature working environment. The selection of the substrate needs to consider the requirements of the final application scenario, including thermal expansion coefficient, electrical insulation performance and mechanical strength and other factors.

[0053] In one possible implementation, the substrate needs to be cleaned by plasma or chemical cleaning before use to remove surface organic matter and particle contaminants. Generally, the plasma cleaning uses oxygen plasma, and the processing time can be adjusted within 30 seconds to 2 minutes, and the gas pressure is controlled between 5Pa and 20Pa. As an option, hydrofluoric acid solution can be used to remove surface oxides of silicon substrate to improve the cleanliness of the substrate surface.

[0054] In some embodiments, the substrate is subjected to a thermal treatment after the cleaning process to release the internal stress and to improve the surface activity. In particular, the thermal treatment is performed at a temperature ranging from 200°C to 300°C for a duration ranging from 5 minutes to 30 minutes to ensure the thermal stability of the substrate surface. As an optimization, the thermal treatment is performed in a nitrogen atmosphere to prevent the oxidation of the substrate surface.

[0055] After the substrate is treated, an insulating layer is deposited on the substrate surface. In the present embodiment, the insulating layer has a thickness ranging from 10 nm to 50 nm and is made of silicon dioxide, aluminum oxide or silicon nitride. In general, the silicon dioxide layer is suitable for a silicon substrate and provides good dielectric properties, while the aluminum oxide layer has a higher thermal stability at high temperatures.

[0056] In a possible implementation, the deposition of the insulating layer is performed by atomic layer deposition or magnetron sputtering. In particular, the atomic layer deposition is performed by alternating the introduction of precursor gases at low temperature to achieve uniform growth, and the deposition rate is generally controlled in the range from 0.1 nm to 0.2 nm per cycle to ensure the density of the insulating layer.

[0057] Alternatively, the magnetron sputtering process can be used to deposit the insulating layer, with a sputtering power ranging from 100 W to 500 W and a sputtering atmosphere of pure argon or argon-oxygen mixture to control the oxygen content and deposition rate of the thin film. In general, the deposition rate is adjusted in the range from 0.2 nm / s to 1 nm / s to obtain a uniform and low-stress insulating layer structure.

[0058] In some embodiments, the surface roughness of the insulating layer is controlled to be less than 1 nm to ensure the uniformity of the thin film. In particular, the surface roughness is measured by atomic force microscopy or ellipsometry to ensure that it is within the optimized range.

[0059] As an optimization, a thermal treatment can be performed after the deposition of the insulating layer to enhance its density and interface stability. In general, the thermal treatment is performed at a temperature ranging from 150°C to 400°C for a duration ranging from 5 minutes to 1 hour. For a silicon dioxide layer, the thermal treatment is performed in an oxygen atmosphere to increase the oxidation level of the thin film, while for an aluminum oxide layer, the thermal treatment is performed in a nitrogen atmosphere to reduce the surface defect density.

[0060] After the surface treatment of the substrate and the deposition of the insulating layer, a thin film needs to be deposited on the surface. The quality of the thin film directly affects the high-frequency performance of the inductor, including key parameters such as permeability, eddy current loss, and Q value. Therefore, in this step, the sputtering process needs to be optimized to reasonably control the proportion of metal elements and accurately adjust the thickness of the thin film to ensure the uniformity and performance stability of the thin film. Generally, the composition, thickness, and microstructure of the thin film have an important influence on its electromagnetic properties, and need to be optimized in combination with the working frequency and target performance requirements of the inductor.

[0061] In this embodiment, the thin film is deposited on the treated substrate using a magnetron sputtering process. The thin film is composed of at least two metal elements, specifically including nickel (Ni), iron (Fe), and cobalt (Co), with a mass ratio range controlled at Ni:Fe:Co = 80:15:5 to 60:30:10. Within this ratio range, the increase of nickel composition helps to improve the permeability, while the introduction of chromium, copper, and vanadium helps to adjust the magnetic anisotropy and saturation magnetization to meet the requirements of high-frequency applications.

[0062] Generally, the thickness of the thin film ranges from 50 nanometers to 200 nanometers. The eddy current loss P e The relationship between the thin film thickness d and the eddy current loss P is as follows:

[0063]

[0064] where σ is the electrical conductivity, B is the magnetic flux density, f is the working frequency, and ρ is the resistivity of the material. As can be seen, the selection of the thin film thickness needs to ensure the permeability while minimizing the eddy current loss. Therefore, in this embodiment, the thin film thickness is adjusted according to the eddy current loss optimization theory to be within the optimal range, so as to reduce the high-frequency loss and ensure the stability of the magnetic response.

[0065] As a possible implementation, the deposition of the thin film uses direct current magnetron sputtering or radio frequency magnetron sputtering. Specifically,

[0066] When the target material is a metal with high electrical conductivity, direct current magnetron sputtering is preferred to improve the deposition rate;

[0067] When the target material contains high-resistance components (such as amorphous or nitrides), radio frequency magnetron sputtering can be used to ensure the quality of the thin film.

[0068] In some embodiments, the sputtering power is set in the range of 300 watts to 600 watts, and the selection of the power needs to consider the balance between the deposition rate and the uniformity of the thin film. Higher power (> 500W) can improve the deposition rate, but may cause an increase in internal stress of the thin film, while lower power (< 350W) may result in a decrease in the density of the thin film. Therefore, in this embodiment, it is preferred to adjust between 400W and 500W to ensure the best film quality.

[0069] As an option, the sputtering atmosphere employs a mixture of argon and nitrogen gas, with a volume ratio controlled at 80%:20%. The argon serves to provide sufficient kinetic energy to facilitate sputtering of the metal target, while the introduction of nitrogen gas adjusts the microstructure of the thin film and improves magnetic stability.

[0070] In a possible optimization scheme, the substrate temperature is controlled at 200°C to 350°C. Lower temperatures (around 200°C) can reduce internal stress of the thin film, while higher temperatures (close to 350°C) help to improve grain growth. Therefore, the substrate temperature needs to be properly adjusted to optimize the microstructure and magnetic parameters of the thin film under different process requirements.

[0071] In some embodiments, to further improve the uniformity and stability of the thin film, an intelligent feedback system is employed to monitor and optimize the deposition process in real time. Specifically,

[0072] The feedback system dynamically adjusts the sputtering parameters by monitoring the film thickness, sputtering rate, and gas flow in real time, to ensure the consistency of film formation;

[0073] In combination with the maximum entropy method to optimize permeability, the deposition rate is precisely controlled according to the minimum loss theory of eddy current, so that the permeability of the thin film reaches the expected value.

[0074] In addition, during the deposition of the thin film, special attention needs to be paid to the control of the grain size. Generally, the relationship between the grain size D, the magnetic anisotropy K, and the permeability μ can be expressed as follows:

[0075]

[0076] As can be seen, smaller grain size helps to reduce magnetic anisotropy and improve permeability. Therefore, in this embodiment, the grain size of the thin film is controlled at 5 nm to 50 nm to ensure good high-frequency magnetic response characteristics.

[0077] In some embodiments, the microstructure of the thin film can be optimized by adjusting the sputtering angle. Specifically,

[0078] When the sputtering angle is set to 0°, a denser thin film structure can be obtained, which helps to reduce magnetic loss;

[0079] When the sputtering angle is set to 15° to 30°, the stress distribution of the thin film can be improved, and the overall stability can be improved.

[0080] As a possible post-processing method, a thermal annealing process can be performed after the thin film deposition to improve the grain boundary structure and reduce internal defects. Generally, the annealing temperature is controlled in the range of 250-450°C, and the annealing time is 10-60 minutes. The specific temperature and time are optimized according to the composition and thickness of the thin film.

[0081] In this embodiment, the magnetic permeability μ r of the thin film is first optimized. The magnetic permeability is affected by the grain size, film stress, and composition ratio, and can be represented by the following relationship:

[0082]

[0083] where μ0 is the free-space magnetic permeability, M s is the saturation magnetization, and K eff is the effective anisotropy constant. To improve the magnetic permeability, M s needs to be increased and K eff needs to be reduced. In this embodiment, the composition of the thin film (Ni-Fe-Co alloy ratio) is adjusted and the microstructure of the grains is optimized to precisely control M s and K eff .

[0084] Specifically, in some embodiments, a gradient composition control method is used to optimize the performance of the thin film. The gradient control method includes:

[0085] During the deposition of the thin film, the nickel, chromium, copper, and vanadium contents are gradually adjusted so that the parameters of the thin film from the substrate to the surface exhibit a gradual change characteristic;

[0086] A multi-layer structure is formed by alternating the deposition of magnetic and non-magnetic layers to improve the high-frequency stability of the thin film.

[0087] In addition, eddy current loss P eddy is an important factor affecting the high-frequency characteristics of the thin film. According to the frequency response characteristics of the material, the eddy current loss can be described by the following formula:

[0088]

[0089] where d is the thickness of the thin film, B max is the maximum magnetic flux density, f is the operating frequency, and ρ is the resistivity of the material. As can be seen, increasing ρ or decreasing d can effectively reduce the eddy current loss. In this embodiment, the thickness of the thin film is optimized to 60-180 nm, and the resistivity is increased by doping non-magnetic elements to reduce the high-frequency loss.

[0090] In one possible implementation, the stress state of the thin film is optimized to reduce the influence of the magnetic anisotropy field H k on the magnetic permeability.

[0091] magnetic anisotropy field H k mainly from internal stress and lattice distortion, the formula is as follows:

[0092]

[0093] In order to reduce H k The embodiment adopts the following technical means:

[0094] Through low-temperature deposition (150-250℃) to control the stress release of the film;

[0095] Adopting plasma assisted deposition technology to adjust the microstructure of the film, so that the stress is uniformly distributed;

[0096] Through subsequent heat annealing treatment (300-400℃, 30-60 minutes) to further optimize the grain arrangement and reduce the internal residual stress.

[0097] As an option, in some embodiments, to further improve the magnetic performance, nano-scale texture structure can be introduced on the surface of the film. The method includes:

[0098] Applying periodic nano-pattern on the surface of the film to change the movement behavior of the magnetic domain wall and improve the anisotropy stability of the film;

[0099] Adjusting the surface roughness by ion etching technology to make the magnetic coupling effect on the surface of the film more uniform, which helps to reduce the high frequency loss.

[0100] In addition, while optimizing the magnetic performance, the mechanical stability and adhesion of the film need to be ensured to improve its long-term working reliability. Generally, the adhesion F adh of the film can be evaluated by the following formula:

[0101] F adh = γ film-sub - γ film-air ;

[0102] Wherein, γ film-sub is the interfacial energy of the film and the substrate, and γ film-air is the free energy of the film surface. By selecting a substrate material with high interfacial energy and performing plasma surface treatment before deposition, the adhesion of the film can be significantly improved.

[0103] In summary, through the optimization of magnetic permeability, minimization of eddy current loss, stress control and surface nano-texturing, etc. The embodiment ensures the stability and low loss performance of the film under high frequency conditions. At the same time, through heat annealing treatment and surface modification technology, the reliability of the film is further improved, providing stable magnetic support for the high frequency application of inductors.

[0104] After the deposition of the thin film, further optimization of its magnetic properties is required to ensure the stability and low loss of the inductor in high-frequency applications. The magnetic permeability, eddy current loss, and anisotropy field strength of the thin film are key factors affecting its performance. Therefore, in this step, the microstructure, thickness, and stress state of the thin film are optimized to ensure that it has a high magnetic permeability and reduces high-frequency loss.

[0105] In this embodiment, low-temperature annealing technology and surface modification technology are used for the surface treatment and subsequent heat treatment process of the thin film to further improve the magnetic and mechanical properties of the thin film. Specifically, after deposition, the surface of the thin film is treated with a high-energy ion beam. Through this treatment, the surface state is optimized, and the surface roughness of the thin film is significantly improved, thereby improving the adhesion and magnetic permeability of the thin film.

[0106] In some embodiments, the annealing temperature is controlled between 200°C and 400°C, which can effectively eliminate the stress inside the thin film while optimizing the arrangement of magnetic domains. The annealing time is usually controlled between 30 minutes and 1 hour to ensure the best balance of annealing effect. During this annealing process, the grain size of the thin film changes to some extent, which affects its magnetic properties. The optimization of the intensity M s and the effective anisotropy constant K eff , the specific changes can be described by the following formula:

[0107]

[0108] where μ0 is the free-space magnetic permeability, M s is the saturation magnetization, and d is the width of the domain wall. During the annealing process, by controlling the temperature and time, the grain size of the thin film is moderate, thereby achieving good magnetic permeability and stable anisotropy.

[0109] As an option, the surface treatment of the thin film can also be performed by plasma-enhanced chemical vapor deposition technology. This technology can generate a uniform thin film cover layer on the surface of the thin film, further improving the magnetic stability and oxidation resistance of the thin film surface. In addition, plasma treatment can form special magnetic nanostructures, such as magnetic nanoparticles, on the surface of the thin film, thereby further improving the high-frequency performance of the thin film.

[0110] Specifically, in some embodiments, to further enhance the mechanical strength and thermal stability of the thin film, nitrogenation treatment can be performed after thermal annealing. Nitrogenation treatment can effectively reduce the residual stress in the thin film and improve its thermal stability. During this process, nitrogen gas diffuses through the interface between the thin film and the substrate, forming a relatively stable nitride layer on the surface of the thin film, thereby improving its high-temperature resistance and oxidation resistance.

[0111] In another possible implementation, the treatment of the film surface can be further optimized by surface rubbing modification. This method forms micro indentation structures on the film surface by micron-level rubbing treatment. These micro indentations can effectively enhance the adhesion between the film and the substrate, thereby improving the stability of the film during long-term operation, especially in high temperature and high humidity environments.

[0112] In this embodiment, the packaging method of the film is first optimized to reduce the influence of the external environment on the performance of the film. Generally, the packaging material must have good mechanical strength, heat resistance, and electrical insulation properties to prevent the film from oxidizing or degrading in performance in a high temperature and high humidity environment. Therefore, a double-layer structure packaging process is adopted, in which the first layer is an inorganic oxide protective layer mainly composed of silicon oxide, aluminum oxide, or silicon nitride to improve chemical corrosion resistance and thermal stability. The second layer is a polymer packaging layer, which selects high-temperature-resistant polyimide or epoxy resin to provide additional mechanical protection.

[0113] In some embodiments, in order to further enhance the bonding force between the packaging layer and the film, a plasma pretreatment technology is used to improve the wettability of the film surface and enhance the interfacial bonding force. By plasma bombardment, the microstructure of the oxide layer on the film surface is restructured, thereby improving the adhesion of the packaging layer. The bonding force of the packaging layer can be calculated by the following formula:

[0114]

[0115] wherein γ substrate is the surface free energy of the film, γ coating is the surface energy of the packaging layer, γ interface represents the interfacial energy, and d is the thickness of the packaging layer. By optimizing the material selection and interface treatment process of the packaging layer, the packaging stability can be effectively improved, and the peeling risk can be reduced.

[0116] As an option, in some embodiments, a sputter deposition method is used to prepare the inorganic packaging layer, which has the advantage of obtaining a dense and uniform protective layer at low temperature, effectively reducing the thermal stress impact of the packaging process on the film. In addition, for the polymer packaging layer, a spin coating method or a spray coating method can be used for preparation, thereby ensuring the uniformity and thickness control of the packaging layer, and the typical thickness range is 1 μm to 5 μm.

[0117] In one possible implementation, in order to meet the thermal stability requirements in high-frequency application environments, the thermal expansion matching properties of the packaging layer are further optimized to reduce the influence of temperature changes on the performance of the film. Specifically, the thermal expansion coefficient σ of the packaging layer should match the substrate material of the film to avoid stress concentration caused by thermal expansion mismatch. The thermal expansion mismatch stress can be represented by the following formula:

[0118]

[0119] Among them, E coating Let α be the elastic modulus of the encapsulation layer. coating and α substrate Here, ν represents the coefficient of thermal expansion of the encapsulation layer and the thin film, respectively, and ν is Poisson's ratio. By optimizing the selection of encapsulation materials, such as using silicon nitride, silicon carbide, or modified polyimide with low coefficients of thermal expansion, the impact of thermal stress on the thin film can be effectively reduced.

[0120] In addition, after encapsulation, interface stability testing is required to verify the environmental resistance of the encapsulation layer. Typically, high temperature and high humidity testing (85℃ / 85%RH, 1000 hours) and thermal shock testing (-40℃ to 125℃, 100 cycles) are used to evaluate the reliability of the encapsulation layer. After testing, scanning electron microscopy is used to observe changes in the microstructure of the encapsulation layer, and energy dispersive spectroscopy is used to detect possible interfacial diffusion phenomena.

[0121] In summary, this embodiment utilizes multiple techniques, including a dual-layer encapsulation structure, plasma pretreatment, thermal expansion matching optimization, and reliability testing, to ensure the long-term stability and environmental resistance of the thin film. These optimization measures further enhance the reliability of the thin film in high-frequency inductors, providing solid technical support for the practical application of high-frequency electronic devices.

[0122] In the preceding steps, the thin film has undergone composition optimization, microstructure adjustment, heat treatment, and interface optimization, thereby improving its permeability, reducing eddy current losses, and enhancing mechanical stability. However, to ensure the suitability of the thin film in high-frequency application environments, further optimization of its structural packaging and interface stability is needed to improve overall durability, resistance to environmental influences, and interface reliability. Therefore, step five mainly involves the final packaging method and interface optimization of the thin film to enhance its stability under high temperature, high humidity, and mechanical stress environments, thereby ensuring the long-term reliability of the thin film and the overall performance of the high-frequency inductor.

[0123] In this embodiment, the encapsulation method of the thin film was first optimized to reduce the impact of the external environment on the film's performance. Generally, encapsulation materials must possess good mechanical strength, heat resistance, and electrical insulation properties to prevent oxidation or performance degradation of the film in high-temperature and high-humidity environments. Therefore, a two-layer encapsulation process was adopted. The first layer is an inorganic oxide protective layer, mainly composed of silicon oxide, aluminum oxide, or silicon nitride, used to improve chemical corrosion resistance and thermal stability. The second layer is a polymer encapsulation layer, selected from high-temperature resistant polyimide or epoxy resin, to provide additional mechanical protection.

[0124] In addition, after the encapsulation is completed, interface stability test needs to be carried out to verify the environmental resistance of the encapsulation layer. Generally, the reliability of the encapsulation layer is evaluated by high temperature and high humidity test (85°C / 85% RH, 1000 hours) and cold and hot impact test (-40°C to 125°C, 100 cycles). After the test, the microstructure change of the encapsulation layer is observed by scanning electron microscope (SEM), and the interface diffusion phenomenon that may occur is detected by energy dispersive spectroscopy (EDS).

[0125] In one embodiment:

[0126] Step 1: Pretreatment of the substrate

[0127] Substrate selection: An alumina ceramic substrate with a purity of ≥99.9% and a surface roughness of ≤5 nm is selected.

[0128] Surface cleaning:

[0129] Ultrasonic cleaning: The substrate surface is sequentially treated in acetone, ethanol and deionized water for 15 minutes each to remove surface contaminants.

[0130] Plasma activation: The substrate surface is treated with a radio frequency power of 100 W for 10 minutes under an argon atmosphere (gas pressure 0.5 Pa) to enhance the adhesion of subsequent film coating.

[0131] Step 2: Vacuum film deposition

[0132] Film coating equipment: A magnetron sputtering film coating system (background vacuum ≤5×10 -5 Pa) is used.

[0133] Target configuration: A nickel-iron alloy target (Ni 80 Fe 20 , purity 99.99%) and a cobalt target (purity 99.95%) are co-sputtered.

[0134] Process parameters:

[0135] Sputtering power: Nickel-iron target 400 W, cobalt target 200 W, power density matching ratio 2:1.

[0136] Gas environment: Argon flow rate 50 sccm, nitrogen flow rate 10 sccm (Ar:N2=83.3%:16.7%), working gas pressure 0.3 Pa.

[0137] Substrate temperature: 250°C, deposition rate controlled at 1.2 nm / s.

[0138] Film thickness: 120 nm (error ±5 nm), monitored in real time by a crystal control instrument.

[0139] Microstructure control:

[0140] Grain size: By adjusting the substrate temperature and sputtering power, the grain size is controlled in the range of 20-30 nm.

[0141] Interface optimization: A 5 nm thick chromium transition layer is pre-deposited between the thin film and the substrate to reduce the interface stress.

[0142] Step three: Vacuum coating deposition of solder layer.

[0143] Process parameters:

[0144] Sputtering power: 300 W, direct current pulse mode (frequency 50 kHz, duty cycle 70%).

[0145] Gas environment: Argon flow 45 sccm, oxygen flow 5 sccm (Ar:O2=90%:10%).

[0146] Substrate temperature: 150°C, deposition rate 1.5 nm / s, total thickness 2 pm (±0.2 pm).

[0147] Interface bonding strength enhancement: A 10 nm thick titanium metal adhesion layer is inserted between the solder layer and the thin film.

[0148] Step four: Double-layer vacuum coating encapsulation

[0149] Inorganic protective layer deposition:

[0150] Process: Plasma enhanced chemical vapor deposition (PECVD).

[0151] Material: Silicon nitride (Si3N4), thickness 50 nm.

[0152] Parameters: SiH4 / NH3 / Ar=10:5:85, radio frequency power 350 W, deposition temperature 300°C.

[0153] Polymer encapsulation layer deposition:

[0154] Process: Vacuum evaporation of polyimide precursor (PMDA-ODA type).

[0155] Parameters: Evaporation source temperature 380°C, substrate temperature 200°C, film thickness 5 pm, after curing a dense encapsulation layer is formed.

[0156] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, replacements and changes can be made to these embodiments without departing from the principles and spirit of the present application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-precision inductor based on magnetron sputtering, characterized in that, include: A thin film deposited on a substrate, wherein the substrate is a carbonyl substrate or an iron-silicon-chromium substrate, and an insulating layer is covered on the surface of the substrate, the thickness of which is 10 nm to 50 nm. The thin film is composed of at least two metallic elements and has a thickness of 50 nm to 200 nm. A solder layer deposited on the surface of the thin film, the solder layer comprising a tin or silver solder layer having a thickness of 1 μm to 3 μm; The magnetic permeability of the thin film is optimized through material composition and microstructure, so that the inductor has eddy current loss of less than 5% and Q value of more than 100 in the target frequency range.

2. A high-precision inductor based on magnetron sputtering according to claim 1, characterized in that, The thin film is composed of at least two elements selected from nickel, chromium, copper, and vanadium.

3. A high-precision inductor based on magnetron sputtering according to claim 1, characterized in that, The surface roughness Ra of the solder layer is ≤2nm to enhance the soldering quality and reduce the interface resistance.

4. A method for forming a high-precision inductor based on magnetron sputtering, comprising the high-precision inductor based on magnetron sputtering as described in any one of claims 1-3, characterized in that... Includes the following steps: Step 1: Deposit an insulating layer on the substrate surface, the insulating layer having a thickness of 10 nm to 50 nm; Step 2: A thin film is deposited on the substrate surface using magnetron sputtering, wherein the proportion of metal elements is adjusted according to the high-frequency performance requirements of the inductor; Step 3: Optimize the magnetic permeability of the thin film using the maximum entropy method, and precisely adjust the film thickness according to the eddy current loss optimization theory to ensure that eddy current loss is minimized; Step 4: Use an intelligent feedback system to monitor and adjust the sputtering power, substrate temperature, and sputtering angle in real time to ensure the uniformity of the film and the optimization of its microstructure. Step 5: A solder layer is deposited on the surface of the thin film using a magnetron sputtering process. The solder layer forms a good bond with the thin film. The solder layer contains tin and silver.

5. The method for forming a high-precision inductor based on magnetron sputtering according to claim 4, characterized in that, The eddy current loss of the thin film is reduced by optimizing the film thickness. The film thickness is optimized within the operating frequency range, and the eddy current loss is proportional to the square of the film thickness. The optimal film thickness is adjusted according to the goal of minimizing eddy current loss.

6. The method for forming a high-precision inductor based on magnetron sputtering according to claim 4, characterized in that, The sputtering power range in the magnetron sputtering process is 300W to 600W, and the atmosphere is a mixture of argon and nitrogen, with the ratio of argon to nitrogen being 80%:20%.

7. The method for forming a high-precision inductor based on magnetron sputtering according to claim 4, characterized in that, The substrate temperature is controlled between 200°C and 350°C to optimize the microstructure of the film and reduce the internal stress of the film.

8. The method for forming a high-precision inductor based on magnetron sputtering according to claim 4, characterized in that, The deposition power of the solder layer is set to 250W to 450W, the thickness of the solder layer is controlled between 1μm and 3μm, the atmosphere of the solder layer is controlled as a mixture of argon and oxygen, the ratio of argon to oxygen is 90%:10%, and the deposition rate of the solder layer is controlled between 0.5nm / s and 2nm / s.

9. A method for forming a high-precision inductor based on magnetron sputtering according to claim 4, characterized in that, The permeability of the thin film was optimized using the maximum entropy method, and the permeability was adjusted according to the composition and structure of the thin film during the optimization process.

10. A method for forming a high-precision inductor based on magnetron sputtering according to claim 4, characterized in that, The high-frequency performance of the inductor is optimized by adjusting the grain size of the thin film and the interface quality between the thin film layers. The grain size is controlled between 5nm and 50nm to reduce magnetic anisotropy and improve the Q value of the inductor.

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