A stacked inductor and its manufacturing method and application

Abstract

The present invention provides a stacked inductor and its manufacturing method and application. The stacked inductor includes a substrate, an inner electrode embedded in the substrate, an outer electrode connected to the side end of the substrate, and a magnetic conductive layer embedded in the stacked inductor. The outer electrode includes an introducing outer electrode and a leading-out outer electrode. The inner electrode includes an intermediate electrode disposed inside the magnetic conductive layer, and a first leading-out electrode and a second leading-out electrode respectively connected to the top and bottom of the intermediate electrode. The first leading-out electrode and the second leading-out electrode respectively pass through through-holes formed on the side surface of the magnetic conductive layer and are in electrical contact with the leading-out outer electrode and the introducing outer electrode. The stacked inductor provided by the present invention can effectively reduce the mutual interference between the external circuit and the inductor winding, improve the signal integrity and transmission efficiency, reduce the risk of system failure rate and performance degradation, and has a simple manufacturing method, which is suitable for commercial applications.

Description

Technical Field

[0001] The present invention belongs to the technical field of inductive components, and relates to a stacked inductor and its preparation method and application. Background Art

[0002] Due to the increasing complexity of modern circuit system design, the market's functional requirements for inductors are becoming more and more diverse. Different circuit designs and application scenarios may require different inductance values and characteristics. In electronic devices, especially in mobile devices and wireless sensor networks with increasing requirements for miniaturization and integration, the mutual interference between electronic components has become an issue worthy of increasing attention.

[0003] An anti-interference inductor is an inductor device that reduces external electromagnetic interference and prevents internal magnetic field leakage through a magnetic conductive material layer. The magnetic conductive material can effectively isolate the inductor winding from the external electromagnetic field, thereby reducing the impact of external interference on the inductor and preventing the magnetic field generated by the inductor from interfering with other circuit parts. At the same time, the anti-interference inductor can effectively filter noise and interference, so it helps to maintain the integrity and stability of the signal, especially outstanding in high-frequency applications. The anti-interference inductor can improve the stability and performance of the entire electronic device, reduce problems such as failures or performance degradation caused by electromagnetic interference, and help ensure the stable operation of the electronic system in a complex environment by reducing electromagnetic interference and improving signal integrity.

[0004] For example, CN218769059U discloses an inductor with anti-interference function, including an inductor structure, and an anti-interference component is arranged outside the inductor structure. Through the provided limit plate, anti-magnetic plate, connecting column, shielding cover, positioning groove, connecting rod, connecting spring, positioning column and anti-interference outer shell, the shielding cover can be installed inside the anti-interference outer shell, and at the same time, the inductor structure can be subjected to anti-interference treatment to avoid electromagnetic interference affecting the normal use of the inductor structure.

[0005] However, the above-mentioned preparation method of the anti-interference inductor is complex, greatly increasing the size of the original inductor, and has limited magnetic shielding effect on high-inductance inductor devices, which is not conducive to commercial application. As a non-wound inductor, the stacked inductor has significant advantages such as a compact structure, no mutual interference, and no directionality compared with traditional wound inductors. Therefore, how to fabricate a highly stable and high-inductance anti-interference stacked inductor under the existing material properties and size conditions is a technical problem that urgently needs to be solved. Summary of the Invention

[0006] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a stacked inductor, a preparation method thereof and an application. The stacked inductor provided by the present invention effectively changes the distribution of the electromagnetic field by embedding a magnetic conductive layer into the interior of the stacked inductor and surrounding the intermediate electrode, reduces the influence of external electromagnetic waves on the inductor winding, and prevents external noise from entering the inductor; especially in high-speed and high-frequency applications, it can effectively reduce signal distortion, improve signal integrity and transmission efficiency, and ensure the accuracy of data transmission; at the same time, it can also suppress the interference of the magnetic field generated by the inductor on the surrounding circuits, reduce the risk of system failure rate and performance degradation, thereby improving the reliability and stability of the overall device; moreover, the preparation method of the stacked inductor provided by the present invention is simple and suitable for commercial application.

[0007] To achieve the purpose of this invention, the following technical solutions are adopted:

[0008] In the first aspect, the present invention provides a stacked inductor, which includes a substrate, an inner electrode buried in the substrate, an outer electrode connected to the side end of the substrate, and a magnetic conductive layer embedded in the stacked inductor; the outer electrode includes an input outer electrode and an output outer electrode, the inner electrode includes an intermediate electrode disposed inside the magnetic conductive layer, and a first lead electrode and a second lead electrode respectively connected to the top and bottom of the intermediate electrode, and the first lead electrode and the second lead electrode respectively pass through a through groove formed on the side surface of the magnetic conductive layer and are in electrical contact with the output outer electrode and the input outer electrode.

[0009] In the present invention, by embedding a magnetic conductive layer surrounding the intermediate electrode in the stacked inductor, the distribution of the electromagnetic field can be effectively changed, the influence of external electromagnetic waves on the inductor winding can be reduced, and external noise can be prevented from entering the inductor; at the same time, it can also suppress the interference of the magnetic field generated by the inductor itself on the surrounding circuits, reduce the risk of system failure rate and performance degradation, thereby improving the reliability and stability of the overall device; moreover, the present invention arranges the magnetic conductive layer inside the stacked inductor, avoiding the large-area exposure of the magnetic conductive layer in the circuit, and can effectively prevent the phenomenon of short circuit due to the contact between the magnetic conductive layer and external metal, thus greatly improving the safety.

[0010] As a preferred technical solution of the present invention, the shape of the magnetic conductive layer includes a cuboid or a curved surface body with the through groove formed on the side surface.

[0011] As a preferred technical solution of the present invention, the center of the magnetic conductive layer coincides with the center of the stacked inductor.

[0012] The vertical distance from the center to the outer wall of the magnetic conductive layer is x times the vertical distance from the center to the edge of the intermediate electrode, and the vertical distance from the center to the outer wall of the stacked inductor is y times the vertical distance from the center to the edge of the intermediate electrode. x ≥ 1.3, y ≥ 1.1x. For example, x = 1.3, y = 1.5; x = 1.4, y = 1.7; x = 1.5, y = 2.0; x = 1.6, y = 2.3; x = 1.7, y = 2.6; or x = 1.8, y = 2.9, etc. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0013] In the present invention, both x and y refer to the proportional relationship of the vertical distances in the same direction. By adjusting the distances between the magnetic conductive layer, the intermediate electrode, and the outer electrode, the anti-interference effect can be further improved, and the safety can be further enhanced.

[0014] The wall thickness of the magnetic conductive layer is 5% - 10% of the maximum vertical distance from the center to the edge of the intermediate electrode. For example, 5%, 6%, 7%, 8%, 9%, or 10%, etc. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0015] In the present invention, the thickness of the magnetic conductive layer can be adjusted according to the size of the inductor, so that the obtained stacked inductor can better balance the inductance value, anti-interference performance, and safety performance.

[0016] As a preferred technical solution of the present invention, the lead-out electrode is a T-shaped structure thin sheet, and the T-shaped structure thin sheet includes an integrally formed contact portion and a connecting portion. The side surface of the contact portion is in electrical contact with the outer electrode, and a through hole is opened at the end of the connecting portion.

[0017] The contact portion of the lead-out electrode and the outer electrode are connected in multiple faces.

[0018] The first lead-out electrode and the second lead-out electrode are mirror structures.

[0019] The connecting portion of the lead-out electrode passes through the through groove.

[0020] Taking the width direction of the connecting portion of the lead-out electrode as the horizontal direction, the length of the through groove in the horizontal direction is 3 - 5 times the width of the connecting portion of the lead-out electrode, and the length of the through groove in the direction perpendicular to the horizontal direction is 3 - 5 times the thickness of the connecting portion of the lead-out electrode. For example, 3.0 times, 3.5 times, 4.0 times, 4.5 times, or 5.0 times, etc. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0021] In the present invention, by adjusting the size of the through groove, a better balance among the inductance value, anti-interference effect, and safety can be achieved.

[0022] As a preferred technical solution of the present invention, the material of the magnetic conductive layer includes metal.

[0023] The material of the magnetic conductive layer includes copper or silver.

[0024] As a preferred technical solution of the present invention, the intermediate electrode comprises a stacked spiral metal layer with the same rotation direction, and a through hole is respectively provided at the head end and the tail end of the spiral metal layer.

[0025] Adjacent spiral metal layers are connected via through-hole columns connected to the through-holes, and the spiral metal layer at the top and the spiral metal layer at the bottom are mirror-image structures.

[0026] The spiral metal layer at the top is connected to the through hole on the first lead-out electrode through a through hole column located at the head end of the spiral metal layer, and the spiral metal layer at the bottom is connected to the through hole on the second lead-out electrode through a through hole column located at the head end of the spiral metal layer.

[0027] The structure of the spiral metal layer includes an elliptical spiral structure.

[0028] In a second aspect, the present invention provides a method for preparing the multilayer inductor according to the first aspect, the method comprising:

[0029] (1) Grooves are formed on the ferrite diaphragm, and a metal conductor is printed in each groove as an inner electrode using a screen printing process;

[0030] (2) spraying the printed electrode surface of the inner electrode with a diluent of the adhesive and drying the adhesive to obtain a substrate;

[0031] (3) embedding a magnetic conductor with a through groove on the side, and the through groove is located away from the metal conductor;

[0032] (4) Cutting along the periphery of the inner electrode to form a laminated inductor body, and exposing a portion of the inner electrode on both sides of the inductor body;

[0033] (5) Heating and keeping the inductor body warm to complete the debinding, and then sintering to fully solidify it;

[0034] (6) Chamfer the sintered semi-finished product and electroplate the outer electrodes on the exposed inner electrodes on both sides of the laminated inductor body.

[0035] The preparation method provided by the present invention only needs to embed a magnetic conductive layer during the preparation process of the stacked inductor, so as to improve the signal integrity and transmission efficiency in high-speed and high-frequency applications, reduce the risk of system failure rate and performance degradation, and improve the reliability and stability of the overall equipment; and the preparation method is simple and suitable for commercial applications.

[0036] As a preferred technical solution of the present invention, holes are drilled at the head and end positions of the groove, and a metal conductor is printed in the hole by screen printing to form a via column.

[0037] The number of the ferrite diaphragms is at least two, such as 2, 3, 4, 5, 6, 7 or 8, etc., but is not limited to the listed values, and other unlisted values within this value range are equally applicable.

[0038] The ferrite diaphragms are stacked and placed, and a laminated part is obtained after warm water isostatic pressing treatment.

[0039] The inner electrodes on two adjacent ferrite diaphragms are connected through the via column.

[0040] As a preferred technical solution of the present invention, the preparation method includes the following steps:

[0041] (1) Grooves are opened on at least two ferrite diaphragms, holes are drilled at the head and end positions of each groove, a metal conductor is printed in each groove as an inner electrode by screen printing, and a metal conductor is printed in each hole to form a via column;

[0042] (2) A diluted solution of an adhesive is sprayed on the printed electrode surface of the inner electrode and dried, then the at least two ferrite diaphragms are stacked and placed, the inner electrodes on each ferrite diaphragm are connected through the via column, and then a laminated part is obtained after warm water isostatic pressing treatment;

[0043] (3) A magnetic conductor with a through groove opened on the side is embedded, and the position of the through groove avoids the metal conductor;

[0044] (4) At least two laminated inductor bodies are formed by cutting along the periphery of the inner electrode, and part of the inner electrode is exposed on both sides of each inductor body;

[0045] (5) The at least two inductor bodies are heated and kept warm to complete degumming, and then sintered to be completely cured;

[0046] (6) The sintered semi-finished product is chamfered, and outer electrodes are electroplated on the inner electrodes exposed on both sides of each laminated inductor body.

[0047] In a third aspect, the present invention also provides an application of the laminated inductor as described in the first aspect in a high-frequency circuit.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] The stacked inductor provided by the present invention effectively changes the distribution of the electromagnetic field by embedding a magnetic conductive layer inside the stacked inductor and surrounding the middle electrode, reduces the influence of external electromagnetic waves on the inductor winding, prevents external noise from entering the inductor. Especially in high-speed and high-frequency applications, it can effectively reduce signal distortion, improve signal integrity and transmission efficiency, and ensure the accuracy of data transmission. At the same time, it can also suppress the interference of the magnetic field generated by the inductor on the surrounding circuits, reduce the risk of system failure rate and performance degradation, thereby improving the reliability and stability of the overall device. Moreover, the method for preparing the stacked inductor provided by the present invention is simple and suitable for commercial applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 FIG. 6 is a schematic structural diagram of the stacked inductor provided in Embodiment 1.

[0051] Figure 2 FIG. 10 is a schematic structural diagram of the magnetic conductive layer provided in Embodiment 1.

[0052] Figure 3 FIG. 14 is a first schematic structural diagram of the middle electrode provided in Embodiment 1.

[0053] Figure 4 FIG. 18 is a second schematic structural diagram of the middle electrode provided in Embodiment 1.

[0054] Figure 5 FIG. 22 is a schematic structural diagram of the first lead electrode provided in Embodiment 1.

[0055] Figure 6 FIG. 26 is a schematic structural diagram of the second lead electrode provided in Embodiment 1.

[0056] Figure 7 FIG. 30 is a performance curve diagram of the stacked inductor provided in Embodiment 1.

[0057] In the figure:

[0058] 1 - Substrate; 2 - Magnetic conductive layer; 3 - Introduced external electrode; 4 - Lead-out external electrode; 5 - Middle electrode; 6 - First lead electrode; 7 - Second lead electrode; 8 - Through groove; 9 - Through hole column; 10 - Contact part; 11 - Connection part. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0059] The technical solutions of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0060] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification, claims, and above-mentioned drawings of this application are intended to cover non-exclusive inclusion.

[0061] Embodiment 1

[0062] This embodiment provides a stacked inductor. As Figure 1 shown, the stacked inductor is in the shape of a cuboid and includes a substrate 1, an inner electrode embedded in the substrate, an introduced outer electrode 3 and a lead-out outer electrode 4 connected to both ends of the substrate, and a magnetic conductive layer 2 embedded inside the stacked inductor; the inner electrode includes an intermediate electrode 5 provided on the inner side of the magnetic conductive layer and a first lead-out electrode 6 and a second lead-out electrode 7 respectively connected to the top and bottom of the intermediate electrode. The first lead-out electrode 6 and the second lead-out electrode 7 respectively pass through a through hole 8 opened on the side surface of the magnetic conductive layer and are in electrical contact with the lead-out outer electrode 4 and the introduced outer electrode 3.

[0063] The specific structure of the magnetic conductive layer is as Figure 2 shown; the specific structure of the intermediate electrode is as Figure 3 and Figure 4 shown, and includes elliptical spiral metal layers arranged in a stacked manner and having the same rotation direction. Adjacent spiral metal layers are connected by via posts 9. The spiral metal layer at the top and the spiral metal layer at the bottom are mirror structures and are respectively connected to the vias on the first lead-out electrode 6 and the second lead-out electrode 7 through the via posts 9 located at the head of the spiral metal layer; the specific structures of the first and second lead-out electrodes are respectively as Figure 5 and Figure 6 shown, and include an integrally formed contact portion 10 and a connection portion 11. The side surface of the contact portion 10 is in electrical contact with the outer electrode.

[0064] Among them, taking the outer wall of the stacked inductor as the standard, the size of the stacked inductor is 2.0 mm × 1.2 mm × 1.0 mm, the overall size of the spiral metal layer is 1.1 mm × 0.7 mm × 0.6 mm, the number of layers is 4, the number of turns of the coil is 4, the width of the coil is 50 μm, and the line thickness is 20 μm; the material of the magnetic conductive layer is copper. Taking the outer wall of the magnetic conductive layer as the standard, the size of the magnetic conductive layer is 1.7 mm × 1.0 mm × 0.9 mm, and the wall thickness is 0.03 mm; the width of the lead-out electrode connection portion is 0.2 mm, the thickness of the lead-out electrode is 0.05 mm, and the size of the through hole is 0.8 mm × 0.2 mm × 0.03 mm.

[0065] Its preparation method is as follows:

[0066] (1) Prepare 4 ferrite diaphragms.

[0067] (2) Grooves are formed on each ferrite diaphragm, and holes are drilled at the bottom of each groove to facilitate subsequent connection between metal layers.

[0068] (3) The screen printing process is used to print metal conductors as electrodes in each groove. The metal conductor before curing is preferably silver paste. The single-layer internal electrode includes a metal layer and a via column. The electrode pattern is printed on the surface of the metal layer, and the via column is printed at the drilled hole.

[0069] (4) Glue spraying: The printing electrode surface of the single-layer internal electrode is sprayed with a diluted solution of the adhesive and dried to cure the liquid silver paste for convenient subsequent operations.

[0070] (5) Four ferrite diaphragms are laminated and pressed according to the spiral direction, so that the internal electrodes on every two adjacent ferrite diaphragms are connected in one-to-one correspondence to form a laminate.

[0071] (6) After four ferrite diaphragms are stacked and preliminarily fixed, a laminate is made under warm water isostatic pressing to preliminarily fix several layers of internal electrodes.

[0072] (8) After the laminate is completed, a metal magnetic conductor with a through groove opened on the side is embedded. Pay attention to avoiding the silver paste layer at the position of the groove hole to prevent short circuit. Cut along the periphery of the internal electrode to form a single stacked inductor body, and make parts of the internal electrodes exposed on both sides of each inductor body. After the ferrite diaphragms are laminated, the internal electrodes in the layer are connected in one-to-one correspondence, and several connected stacked inductor bodies are formed in the laminate. Cut along the periphery of the body so that parts of the internal electrodes are exposed on both sides of each body, facilitating subsequent attachment of external electrodes.

[0073] (8) Debinding and sintering: Heat the body, then keep it warm for a certain time to complete debinding, and then sinter it to make it completely cured.

[0074] (9) Chamfer the sintered semi-finished product, and electroplate metal external electrodes after applying silver to the internal electrodes exposed on both sides of each single stacked inductor body.

[0075] Embodiment 2

[0076] This embodiment provides a stacked inductor, whose structure is the same as that of Embodiment 1.

[0077] Among them, taking the outer wall of the stacked inductor as the standard, the size of the stacked inductor is 2.5 mm × 2.0 mm × 1.0 mm, the overall size of the spiral metal layer is 1.1 mm × 0.7 mm × 0.6 mm, the number of layers is 4, the number of turns of the coil is 4, the width of the coil is 50 μm, and the thickness of the wire is 20 μm; the material of the magnetic conductive layer is copper, taking the outer wall of the magnetic conductive layer as the standard, the size of the magnetic conductive layer is 2.2 mm × 1.8 mm × 0.9 mm, and the wall thickness is 0.03 mm; the width of the lead electrode connection part is 0.2 mm, the thickness of the lead electrode is 0.05 mm, and the size of the through groove is 0.8 mm × 0.2 mm × 0.03 mm.

[0078] The preparation method is the same as that in Example 1.

[0079] Example 3

[0080] This example provides a stacked inductor. The shape of the stacked inductor is a cuboid, and the shape of the magnetic conductive layer is an ellipsoid. The rest of the structure is the same as that in Example 1.

[0081] Among them, taking the outer wall of the stacked inductor as the standard, the size of the stacked inductor is 3.2 mm × 2.5 mm × 1.0 mm, the overall size of the spiral metal layer is 1.1 mm × 0.7 mm × 0.6 mm, the number of layers is 4, the number of turns of the coil is 4, the width of the coil is 50 μm, and the thickness of the wire is 20 μm; the material of the magnetic conductive layer is silver, taking the outer wall of the magnetic conductive layer as the standard, the size of the magnetic conductive layer is 2.9 mm × 2.2 mm × 0.9 mm, and the wall thickness is 0.03 mm; the width of the lead electrode connection part is 0.2 mm, the thickness of the lead electrode is 0.05 mm, and the size of the through groove is 0.8 mm × 0.2 mm × 0.03 mm.

[0082] The preparation method is the same as that in Example 1.

[0083] Example 4

[0084] The difference between this example and Example 1 is that the thickness of the magnetic conductive layer in this example is 0.015 mm.

[0085] The rest of the preparation method and parameters are the same as those in Example 1.

[0086] Example 5

[0087] The difference between this example and Example 1 is that the thickness of the magnetic conductive layer in this example is 0.07 mm.

[0088] The rest of the preparation method and parameters are the same as those in Example 1.

[0089] Comparative Example 1

[0090] The difference between this example and Example 1 is that the magnetic conductive layer is not provided.

[0091] The remaining preparation methods and parameters are the same as those in Example 1.

[0092] Performance Test

[0093] Under the test condition of 1 MHz, the performance of the stacked inductors provided in Examples 1-5 and Comparative Example 1 was tested, and the test results are shown in Table 1:

[0094] Table 1

[0095]

[0096] From Figure 7 the comparison between Examples 1-3 and Comparative Example 1 in Table 1, it can be seen that by setting magnetic conductive layers with different sizes in stacked inductors of different sizes, compared with the stacked inductors without magnetic conductive layers, while achieving the anti-interference effect, it has no obvious impact on the inductance value and quality factor of the inductor; this also shows that the stacked inductor provided by the present invention can effectively reduce the mutual interference between the external circuit and the inductor winding without affecting the inductance value and its quality factor of the inductor, improve the signal integrity and transmission efficiency, reduce the risk of system failure rate and performance degradation, and the preparation method is simple and suitable for commercial application.

[0097] From the comparison between Examples 4-5 and Example 1 in Table 1, it can be seen that the thickness of the magnetic conductive layer will affect the inductance value of the stacked inductor. When the wall thickness of the magnetic conductive layer is in the range of 5% to 10% of the maximum vertical distance from the center to the edge of the middle electrode, a better balance between the inductance value and the anti-interference effect of the inductor can be achieved. In practical applications, different thicknesses of the magnetic conductive layer can be selected according to needs.

[0098] The applicant declares that the above description is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A multilayer inductor, characterized in that: The laminated inductor comprises a substrate, an inner electrode buried in the substrate, an outer electrode connected to a side end of the substrate, and a magnetic conductive layer embedded in the laminated inductor; The external electrode includes an introduction external electrode and an extraction external electrode, the internal electrode includes an intermediate electrode arranged inside the magnetic conductive layer and a first extraction electrode and a second extraction electrode respectively connected to the top and bottom of the intermediate electrode, the first extraction electrode and the second extraction electrode respectively pass through the through grooves provided on the side of the magnetic conductive layer to electrically contact the extraction external electrode and the introduction external electrode; The material of the magnetic conductive layer includes copper or silver; The center of the magnetic conductive layer coincides with the center of the laminated inductor, and the wall thickness of the magnetic conductive layer is 5% to 10% of the maximum vertical distance from the center to the edge of the middle electrode.

2. The multilayer inductor according to claim 1, characterized in that: The shape of the magnetic conductive layer includes a rectangular parallelepiped or a curved body with the through grooves opened on the side.

3. The multilayer inductor according to claim 1, characterized in that: The vertical distance from the center to the outer wall of the magnetic conductive layer is x times the vertical distance from the center to the edge of the middle electrode, and the vertical distance from the center to the outer wall of the laminated inductor is y times the vertical distance from the center to the edge of the middle electrode, x≥1.3, y≥1.1x.

4. The multilayer inductor according to claim 1, characterized in that: The lead-out electrode is a T-shaped thin sheet, and the T-shaped thin sheet includes an integrally formed contact portion and a connecting portion, the side surface of the contact portion is in electrical contact with the external electrode, and a through hole is provided at the end of the connecting portion; The contact portion of the extraction electrode is connected to the external electrode on multiple surfaces; The first lead-out electrode and the second lead-out electrode are mirror-image structures; The connecting portion of the lead-out electrode passes through the through groove; Taking the width direction of the lead-out electrode connecting portion as the horizontal direction, the length of the through groove along the horizontal direction is 3 to 5 times the width of the lead-out electrode connecting portion, and the length of the through groove along the vertical and horizontal directions is 3 to 5 times the thickness of the lead-out electrode connecting portion.

5. The multilayer inductor according to claim 1, characterized in that: The intermediate electrode comprises a stacked spiral metal layer with the same rotation direction, and a through hole is respectively provided at the head end and the tail end of the spiral metal layer; The adjacent spiral metal layers are connected via a through-hole column connected to the through-hole, and the spiral metal layer at the top and the spiral metal layer at the bottom are mirror-image structures; The spiral metal layer at the top is connected to the through hole on the first lead-out electrode through a through hole column located at the head end of the spiral metal layer, and the spiral metal layer at the bottom is connected to the through hole on the second lead-out electrode through a through hole column located at the head end of the spiral metal layer; The structure of the spiral metal layer includes an elliptical spiral structure.

6. A method for preparing a multilayer inductor as claimed in claim 1, characterized in that: The preparation method comprises: (1) Grooves are formed on the ferrite diaphragm, and a metal conductor is printed in each groove as an inner electrode using a screen printing process; (2) spraying the printed electrode surface of the inner electrode with a diluent of the adhesive and drying the adhesive to obtain a substrate; (3) embedding a magnetic conductor with a through groove on the side, and the through groove is located away from the metal conductor; (4) Cutting along the periphery of the inner electrode to form a laminated inductor body, and exposing a portion of the inner electrode on both sides of the inductor body; (5) Heating and keeping the inductor body warm to complete the debinding, and then sintering to fully solidify it; (6) Chamfer the sintered semi-finished product and electroplate the outer electrodes on the exposed inner electrodes on both sides of the laminated inductor body.

7. The method for preparing a multilayer inductor according to claim 6, characterized in that: Drill holes at the beginning and the end of the groove, and print metal conductors in the holes using a screen printing process to form through-hole columns; The number of the ferrite diaphragms is at least two; The ferrite diaphragms are stacked and subjected to warm water isostatic pressing to obtain a laminate; The inner electrodes on two adjacent ferrite diaphragms are connected through the through-hole column.

8. The method for preparing a multilayer inductor according to claim 6, characterized in that: The preparation method comprises: (1) grooves are formed on at least two ferrite diaphragms, holes are punched at the beginning and end of each groove, a metal conductor is printed in each groove as an inner electrode by a screen printing process, and a metal conductor is printed in each hole to form a through-hole column; (2) spraying the printed electrode surface of the inner electrode with a diluent of the adhesive and drying it, then stacking the at least two ferrite diaphragms, connecting the inner electrodes on each ferrite diaphragm through the through-hole column, and then performing warm water isostatic pressing to obtain a laminate; (3) embedding a magnetic conductor with a through groove on the side, and the through groove is located away from the metal conductor; (4) cutting along the periphery of the inner electrode to form at least two laminated inductor bodies, and exposing a portion of the inner electrode on both sides of each inductor body; (5) heating and keeping warm at least two inductor bodies to complete debinding, and then sintering to fully solidify them; (6) The sintered semi-finished product is chamfered and external electrodes are electroplated on the exposed internal electrodes on both sides of each laminated inductor body.

9. Use of the multilayer inductor according to any one of claims 1 to 5 in a high-frequency circuit.

Images