Laminated inductor and preparation method thereof

Abstract

The invention belongs to the technical field of laminated inductors, and discloses a laminated inductor and a preparation method thereof. The laminated inductor comprises an inner electrode and an outer electrode, the inner electrode comprises a plurality of metal layers arranged in a laminated mode, the adjacent metal layers are connected through through hole layers, and each metal layer is in a planar spiral shape and is provided with a center end and an outer side end. The central end and the outer side end of the metal layer located at the middle layer are used for being connected with the through hole layer, and the outer side ends of the metal layers located at the top layer and the bottom layer are used for being connected with an outer electrode. The laminated inductor is high in inductance value and good in stability.

Description

Technical Field

[0001] The present invention relates to the technical field of laminated inductors, and in particular to laminated inductors and a preparation method thereof. Background Art

[0002] With the rapid development of electronic communication technology, as well as the continuous upgrading of mobile communication technology and digital communication networks, the miniaturization and high performance of electronic components are the general trend. As an important component in the electromagnetic field, the market demand for inductors is very large. Stacked inductors are also called non-winding inductors. Compared with winding inductors, the advantages of stacked inductors are small structural size, no mutual interference and no directionality. However, due to the limitations of the material performance and the spatial size of the inductor, the upper limit of the inductance value of stacked inductors is prone to bottlenecks.

[0003] With the increasing complexity of modern circuit system design, the structure of electrodes in the stack is becoming more and more diverse. Generally speaking, in order to increase the inductance of a stacked inductor, the number of electrode layers is generally increased to achieve an increase in inductance. However, due to the height limitation of the inductor itself, the number of layers cannot be increased indefinitely, so the height size of the inductor itself limits the upper limit of the inductance. For example, the application with patent number CN217881126 discloses a high energy density stacked inductor. The technology provides electromagnetic shielding and optimizes the connection method of the inductor, but the structure is more complicated than the general stacked inductor, and the performance is not essentially improved; the application with patent number CN113363048A discloses a method for making a stacked inductor with a simple structure. The stacked inductor made by this technology has a high quality factor, but due to structural limitations, it is difficult to make a high inductance inductor; the application with patent number CN102637505A discloses a high self-resonant frequency stacked inductor, which achieves a high quality factor, but due to the simple structure, it is generally suitable for small inductance inductors.

[0004] Therefore, there is an urgent need to propose a multilayer inductor and a preparation method thereof to solve the above problems. Summary of the invention

[0005] An object of the present invention is to provide a multilayer inductor having high inductance and good stability.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] A laminated inductor, comprising an inner electrode and an outer electrode, wherein the inner electrode comprises a plurality of stacked metal layers, adjacent metal layers are connected via a through-hole layer, and the metal layer is in a planar spiral shape and has a central end and an outer end;

[0008] The central end and the outer ends of the metal layer located in the middle layer are used to connect to the through-hole layer, and the outer ends of the metal layers located in the top layer and the bottom layer are used to connect to the external electrodes.

[0009] Optionally, the through-hole layer includes through-hole columns, and two adjacent layers of the through-hole columns are connected to different ends of the metal layer.

[0010] Optionally, a groove is provided on the metal layer, and the groove is used to accommodate the metal conductor.

[0011] Optionally, the metal conductor is silver paste.

[0012] Optionally, the inner electrode is in the shape of a waist spiral, a circular spiral or a square spiral.

[0013] Another object of the present invention is to provide a method for preparing a multilayer inductor, which has high efficiency and low cost; the multilayer inductor prepared by the method has high inductance and good stability.

[0014] To achieve this object, the present invention adopts the following technical solutions:

[0015] A method for preparing a multilayer inductor, including the multilayer inductor described above, comprises the following steps:

[0016] S100, forming a groove on the metal sheet, and drilling a hole at a position where the metal sheet is connected to the through-hole column;

[0017] S200, printing a metal conductor on the punched metal sheet using a screen printing process, forming an electrode pattern on the surface of the metal sheet, and forming the through-hole column by printing at the punched area;

[0018] S300, spraying glue on the metal sheet and drying it to solidify the metal conductor;

[0019] S400, stacking and pressing the metal sheets and the through-hole columns in an alternating order, and then cutting, debinding and sintering in sequence to form a metal layer and a through-hole layer, so as to obtain the inner electrode;

[0020] S500 , connecting outer ends of the metal layers at the top layer and the bottom layer to the external electrodes.

[0021] Optionally, the groove is formed by laser etching.

[0022] Optionally, the outer ends of the metal layers of the top layer and the bottom layer are connected to the external electrodes by sequentially electroplating nickel and soldering.

[0023] Optionally, the outer ends of the metal layers of the top layer and the bottom layer are connected to the external electrodes by sequentially electroplating nickel and soldering.

[0024] Optionally, in S500, the pressing is performed by an isostatic pressing process.

[0025] Optionally, in S500, the sintering temperature is 800-950° C., and the sintering holding time is 0.5-2.5 h.

[0026] Beneficial effects:

[0027] The laminated inductor provided by the present invention uses multiple planar spiral metal layers and is connected through a through-hole layer. Since the metal layer is planar spiral, the inductance value is greatly improved, thereby reducing the number of internal electrode layers required. Under the same material and space size restrictions, when there is a demand for the inductance value of the laminated inductor, when the number of internal electrode layers reaches the upper limit, the structure is used to achieve a breakthrough in inductance performance, and the inductance value can be adjusted according to the number of turns of the metal layer.

[0028] The preparation method provided in this embodiment is used to prepare the laminated inductor. Since the laminated inductor has a simple structure, the production efficiency is high and the production cost is low. When there is a demand for a higher inductance value, under the conditions of the same material and space size restrictions, the structure is conducive to improving the inductance value. The number of metal layers and through-hole layers located in the middle layer and the number of spiral turns on the single-layer metal sheet can be adjusted according to the demand for inductance value. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present invention and these drawings without paying any creative work.

[0030] Figure 1 is an exploded diagram of the multilayer inductor provided by the present invention;

[0031] Figure 2 It is a schematic diagram of the local structure of the multilayer inductor provided by the present invention;

[0032] Figure 3 is a side view of the inner electrode provided by the present invention;

[0033] Figure 4 is a schematic structural diagram of the inner electrode provided by the present invention;

[0034] Figure 5 is a top view of the top metal layer provided by the present invention;

[0035] Figure 6 is a top view of the second metal layer provided by the present invention;

[0036] Figure 7 is a top view of the third metal layer provided by the present invention;

[0037] Figure 8 is a top view of the bottom metal layer provided by the present invention;

[0038] Fig. 9 This is the test result of the multilayer inductor provided by the present invention.

[0039] In the figure:

[0040] 1000, inner electrode; 100, metal layer; 101, top metal layer; 102, second metal layer; 103, third metal layer; 104, bottom metal layer; 110, center end; 120, outer end; 200, through-hole layer; 210, through-hole column; 2000, outer electrode. DETAILED DESCRIPTION

[0041] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions, and the first feature "above", "above" and "above" the second feature include the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. The first feature "below", "below" and "below" the second feature include the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0043] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0044] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0045] See also Figures 1 to 3 The laminated inductor includes an inner electrode 1000 and an outer electrode 2000. The inner electrode 1000 includes a plurality of stacked metal layers 100. Adjacent metal layers 100 are connected by through-hole layers 200. The metal layers 100 are planar spirals and have a central end 110 and an outer end 120. The central end 110 and the outer end 120 of the metal layer 100 located in the middle layer are used to connect to the through-hole layer 200, and the outer ends 120 of the metal layers 100 located in the top layer and the bottom layer are used to connect to the outer electrode 2000.

[0046] The above-mentioned stacked inductor adopts a plurality of planar spiral metal layers 100, which are connected through a through-hole layer 200. Since the metal layer 100 is in a planar spiral shape, the inductance is greatly improved, thereby reducing the number of layers of the internal electrode 1000. Under the same material and space size restrictions, when there is a demand for the inductance of the stacked inductor, when the number of layers of the internal electrode 1000 reaches the upper limit, this structure is used to achieve a breakthrough in inductance performance, and the inductance can be adjusted according to the number of turns of the metal layer 100.

[0047] See also Figure 4 , the through-hole layer 200 includes a through-hole column 210, and two adjacent layers of through-hole columns 210 are connected to different ends of the metal layer 100. Without interfering with the spiral, the current can enter from the outer end 120 of the top, then pass through the inner electrode 1000 in a spiral shape, and then flow out from the outer end 120 of the bottom. Of course, it can also enter from the outer end 120 of the bottom and then flow out from the outer end 120 of the top. By staggering the through-hole columns 210, it is ensured that the current has the same rotation direction when flowing through each metal layer 100.

[0048] See also Figures 4 to 8 The multilayer inductor in this embodiment includes four metal layers 100. Figure 5 Shown is the top metal layer 101, Figure 6 The second metal layer 102 is shown. Figure 7 is the third metal layer 103, Figure 8 The bottom metal layer 104. In other embodiments, the number of the metal layers 100 can be three, five or six, etc., which is specifically set according to the space size inside the multilayer inductor.

[0049] See also Figures 5 to 8The metal layer 100 in this embodiment is in the shape of a waist-shaped spiral. In other embodiments, the metal layer 100 may be in the shape of a circular spiral or a square spiral, etc., and may be configured according to the needs of use, and is not specifically limited here.

[0050] Furthermore, a groove is formed on the metal layer 100, and the groove opening is arranged upwards for accommodating the metal conductor. Optionally, the metal conductor may be silver paste, and in other embodiments, other metal materials may be selected as long as they have good conductivity.

[0051] Furthermore, the depth of the groove is set according to actual needs, and the groove can be formed by laser etching or other grooving methods.

[0052] Furthermore, this embodiment also provides a method for preparing a multilayer inductor, including the multilayer inductor described above, the method comprising the following steps:

[0053] S100, a groove is formed on the metal sheet, and a hole is punched at a position where the metal sheet is connected to the through-hole column 210;

[0054] S200, using screen printing technology to print a metal conductor on the punched metal sheet, printing to form an electrode pattern on the surface of the metal sheet, and printing to form a through-hole column 210 at the punched position;

[0055] S300, spraying glue on the metal sheet and drying it to solidify the metal conductor;

[0056] S400, stacking and pressing the metal sheets and the through-hole columns 210 in an alternating order, and then cutting, debinding and sintering in sequence to form the metal layer 100 and the through-hole layer 200, that is, obtaining the internal electrode 1000;

[0057] S500 , the outer ends 120 of the top and bottom metal layers 100 are connected to the external electrodes 2000 .

[0058] The above method is used to make a laminated inductor. Due to its simple structure, it has high production efficiency and low production cost. When there is a demand for a higher inductance value, under the conditions of the same material and space size restrictions, this structure is conducive to improving the inductance value. The number of metal layers 100 and through-hole layers 200 located in the middle layer and the number of spiral turns on a single-layer metal sheet can be adjusted according to the demand for inductance value.

[0059] Optionally, the metal sheet is a ferrite film. It should be noted that when the metal sheets are stacked, they should be arranged according to the spiral direction of the metal sheets, so that the current in each metal layer 100 has the same rotation direction.

[0060] Preferably, in S400, the pressing is performed by isostatic pressing. The isostatic pressing pressure is 10 to 50 MPa, and can be 10 MPa, 20 MPa, 30 MPa, 40 MPa or 50 MPa, etc., to achieve preliminary fixation of the inner electrode 1000. Preferably, the static pressing temperature is 60 to 90°C, and can be 60°C, 70°C, 80°C or 90°C, etc. The static pressing temperature is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0061] The metal sheets and through-hole columns 210 are stacked and pressed together to form a laminate, which is then cut around four sides to form a semi-finished inner electrode. The outer ends 120 of the top and bottom layers are exposed to expose a portion of the metal sheet to form a connection portion, facilitating the subsequent attachment of the outer electrode 2000.

[0062] Furthermore, during the debinding process, the inner electrode semi-finished product is heated, then kept warm for a certain period of time, and then sintered to completely solidify it. The sintering temperature is 800-950° C., and the holding time is 0.5-2.5 hours.

[0063] After sintering, the end of the connection portion is chamfered to form the inner electrode 1000, and the outer electrode 2000 is electroplated after being dipped in silver, for example, by electroplating nickel and solder in sequence, so that the outer electrode 2000 is connected to the inner electrode 1000 and has good solderability and resistance.

[0064] Optionally, the outer ends 120 of the top and bottom metal layers 100 and the outer electrodes 2000 are connected by sequentially electroplating nickel and soldering.

[0065] Fig. 9 The results of a 4-layer diaphragm laminated inductor embodiment are shown. The size of the laminated inductor is 1.6mm×0.8mm×0.8mm, the ferrite diaphragm is 4 layers, the width is 50μm, the line thickness is 20μm, and at 1MHz, the inductance is 7.145uH and the Q value is 11. Compared with similar laminated inductors, this embodiment uses only four metal layers 100 to achieve high inductance, reduces the number of ferrite layers, and effectively reduces production costs.

[0066] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A multilayer inductor, characterized in that: The invention comprises an inner electrode (1000) and an outer electrode (2000), wherein the inner electrode (1000) comprises a plurality of stacked metal layers (100), adjacent metal layers (100) are connected via a through-hole layer (200), and the metal layer (100) is in a planar spiral shape and has a central end (110) and an outer end (120); The central end (110) and the outer end (120) of the metal layer (100) located in the middle layer are used to connect to the through-hole layer (200), and the outer ends (120) of the metal layers (100) located in the top layer and the bottom layer are used to connect to the external electrode (2000).

2. The multilayer inductor according to claim 1, characterized in that: The through-hole layer (200) comprises through-hole columns (210), and two adjacent layers of through-hole columns (210) are connected to different ends of the metal layer (100).

3. The multilayer inductor according to claim 1, characterized in that: The metal layer (100) is provided with a groove, and the groove is used to accommodate a metal conductor.

4. The method for preparing a multilayer inductor according to claim 3, characterized in that: The metal conductor is silver paste.

5. The multilayer inductor according to claim 1, characterized in that: The inner electrode (1000) is in the shape of a waist spiral, a circular spiral or a square spiral.

6. A method for preparing a multilayer inductor, comprising the multilayer inductor according to any one of claims 1 to 5, characterized in that: The following steps are involved: S100, forming a groove on the metal sheet, and drilling a hole at a position where the metal sheet is connected to the through-hole column (210); S200, using a screen printing process to print a metal conductor on the punched metal sheet, printing to form an electrode pattern on the surface of the metal sheet, and printing to form the through-hole column (210) at the punched position; S300, spraying glue on the metal sheet and drying it to solidify the metal conductor; S400, stacking and pressing the metal sheets and the through-hole columns (210) in an alternating order, and then cutting, debinding and sintering in sequence to form a metal layer (100) and a through-hole layer (200), thereby obtaining the inner electrode (1000); S500, the outer ends (120) of the top and bottom metal layers (100) are connected to the external electrodes (2000).

7. The method for preparing a multilayer inductor according to claim 6, characterized in that: The groove is formed by laser etching.

8. The method for preparing a multilayer inductor according to claim 6, characterized in that: The outer ends (120) of the metal layers (100) at the top layer and the bottom layer and the outer electrodes (2000) are connected by sequentially electroplating nickel and soldering.

9. The method for preparing a multilayer inductor according to claim 6, characterized in that: In S500, the pressing is performed by isostatic pressing.

10. The method for preparing a multilayer inductor according to claim 6, characterized in that: In S500, the sintering temperature is 800-950° C., and the sintering holding time is 0.5-2.5 h.

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