A novel inductor and its manufacturing method

Abstract

The present invention discloses a novel inductor and its manufacturing method. The inductor includes N metal layers of the same size and a central magnetic core, where N is a positive integer greater than or equal to 2. The first metal layer to the Nth metal layer are stacked in sequence, and an insulating material is filled between the metal layers. There is one interlayer via on both the first metal layer and the Nth metal layer, and there are two interlayer vias on each of the intermediate metal layers. The electrical signal is transmitted to the metal layer of the next layer through the interlayer via. The central magnetic core is located at the middle position of each metal layer, and the central magnetic core has no electrical connection with each metal layer. The novel inductor designed by the present invention forms a ferromagnetic magnetic core of a spatial spiral inductor by setting a solid nickel cylinder-like central magnetic core at the center of each metal layer. Compared with traditional discrete inductor components, the inductor of the present invention has low cost, few processes, and high reliability; the inductance value and Q value of the inductor of the present invention can be increased by dozens to hundreds of times.

Description

Technical Field

[0001] The present invention relates to the technical field of high-frequency / radio frequency device design, and in particular to a novel inductor and a processing method thereof. Background Art

[0002] Inductors are commonly used in the field of high-frequency and radio frequency equipment, and have an important impact on the performance of high-frequency and radio frequency devices. There are currently two main solutions for the inductor on the substrate of the RF front-end device in the industry. The mainstream is to use discrete inductor devices. In recent years, integrated inductor devices on emerging substrates have emerged, that is, a wire-wound inductor structure is formed through the wiring on the substrate and the vias on the substrate to form an inductor with a specific inductance value, as shown below Figure 1 As shown, the signal passes through the first metal layer (1) through the interlayer via 1 (11) to the second metal layer (2), and then through the interlayer via 2 (21) to the third metal layer (3) (the three-layer substrate is only an example here, and the multi-layer substrate is similar), and the interlayer metal forms a spatial spiral inductor. The mainstream solution uses discrete devices. Although the process is mature, it will increase material costs and process costs, and the module yield will be reduced due to the failure of the inductor device itself and SMT failure. The emerging integrated inductor solution on the substrate is difficult to achieve an inductor with satisfactory inductance and Q value due to the problems of substrate material loss and substrate space limitation. Summary of the invention

[0003] In view of the shortcomings of the current mainstream solutions and emerging solution technologies, the present invention proposes a design and processing solution that can realize the integration of inductance on the substrate and greatly improve the inductance value and Q value. At the same time, the processing method of the present invention is simple, low in cost, with fewer steps and high reliability.

[0004] The present invention is achieved through the following technical solutions:

[0005] A novel inductor, characterized in that the inductor comprises N metal layers of the same size and a central magnetic core, wherein N is a positive integer greater than or equal to 2; the first metal layer to the Nth metal layer are stacked in sequence, and insulating materials are filled between the metal layers; the first metal layer and the Nth metal layer are each provided with an interlayer via, and the middle metal layer is each provided with two interlayer vias, and electrical signals are transmitted to the next metal layer through the interlayer vias; the central magnetic core is located in the middle of each metal layer, and the central magnetic core has no circuit connection with each metal layer.

[0006] Furthermore, the insulating material is epoxy resin.

[0007] Furthermore, the central magnetic core is a solid cylinder formed by processing nickel.

[0008] Furthermore, the diameter of the interlayer via hole is 40-50 μm.

[0009] Further, the diameter of the central magnetic core is 60 - 100 μm.

[0010] Further, the inductor includes N metal layers of the same size and a central magnetic core, where N is a positive integer greater than or equal to 3.

[0011] Specifically, the novel inductor designed in the present invention forms a ferromagnetic magnetic core for a spatial spiral inductor by arranging a solid - like nickel cylinder central magnetic core at the center of each metal layer. Compared with traditional discrete inductor components, the novel inductor designed in the present invention has low cost, excellent performance, and good reliability. The present invention selects nickel as the manufacturing material for the central magnetic core, which can increase the inductance value and Q value of the inductor by dozens to hundreds of times.

[0012] A processing method of a novel inductor, characterized in that the method comprises the following steps:

[0013] S1. According to the shape of the first metal layer, apply a chemical solution to a specified area on the substrate, etch away the excess substrate to form the first metal layer, and there is one inter - layer via on the first metal layer;

[0014] S2. Under high - temperature and high - pressure environments, stack a second substrate on the first metal layer, and one side of this layer of substrate is coated with epoxy resin, the epoxy resin contacts the first metal layer, apply a chemical solution to a specified area on the other side of this layer of substrate, etch away the excess substrate to form the second metal layer, and there are two inter - layer vias on the second metal layer;

[0015] S3. Under high - temperature and high - pressure environments, stack a third substrate on the second metal layer, and one side of this layer of substrate is coated with epoxy resin, the epoxy resin contacts the second metal layer, then apply a chemical solution to a specified area on the other side of this layer of substrate, etch away the excess substrate to form the third metal layer, and there are two inter - layer vias on the third metal layer; and so on, repeat the above process, stack the Nth substrate on the (N - 1)th metal layer, and then etch away the excess substrate through the chemical solution to form the Nth metal layer, and there is one inter - layer via on the Nth metal layer;

[0016] S4. Then drill holes in the epoxy resin, and the drilled holes do not contact the metal layers;

[0017] S5. Electroplate nickel into the holes opened in step S4 to form the central magnetic core, thus completing the processing of the novel inductor.

[0018] Further, the processing method of the novel inductor further comprises the following steps:

[0019] S5-1. Prepare a cover plate and machine a nickel plating hole on the cover plate, and the diameter of the nickel plating hole is the same as the hole diameter in step S4;

[0020] S5-2. Stack the cover plate on the outermost metal layer and align the nickel plating hole completely with the hole opened in step S4;

[0021] S5-3. Nickel plate from the side of the cover plate through the nickel plating hole into the hole opened in step S4 to form the central magnetic core, that is, complete the processing of the novel inductor.

[0022] Further, for the processing method of the novel inductor, the thickness of the substrate is 10 - 30 μm, and the thickness of the epoxy resin coated on the substrate is 20 - 40 μm.

[0023] Specifically, by setting a cover plate and machining a hole for nickel plating on the cover plate, the problem of nickel material sputtering when directly nickel plating into the hole in step S4 can be avoided. That is, in this way, only a cylindrical magnetic core can be formed in the hole of the epoxy resin during nickel plating, and nickel exposure during nickel plating will not occur, which can make the processed inductor have excellent performance and high reliability.

[0024] Further, for the processing method of the novel inductor, the substrate is a copper sheet.

[0025] Further, for the processing method of the novel inductor, the cover plate is a steel plate.

[0026] Specifically, the processing technology of the novel inductor of the present invention has low cost, few processes and high reliability compared with traditional discrete inductor components. The relative magnetic permeability of nickel is 1120, and the relative magnetic permeability of nickel alloy is 10 - 60000. Therefore, the present invention's solution can increase the inductance value and Q value of the substrate integrated inductor by dozens to hundreds of times without increasing the substrate space. At the same time, the nickel plating process is mature, simple, low-cost, easy to process and implement, and has high reliability. Therefore, the high-frequency / radio frequency front-end devices produced according to this will have excellent performance and better reliability.

[0027] Specifically, the liquid medicine can only corrode the redundant substrate (copper sheet) material and cannot corrode the epoxy resin coated on the substrate. Therefore, the central magnetic core is fixed by the epoxy resin on the substrate. Under the condition that the central magnetic core is not connected to each metal layer, the central magnetic core can still form an integral inductor device with each substrate.

[0028] The beneficial effects of the present invention:

[0029] The novel inductor designed by the present invention forms a ferromagnetic core for a spatial spiral inductor by arranging a solid nickel cylinder-like central magnetic core at the center of each metal layer. Compared with traditional discrete inductor devices, the novel inductor designed by the present invention has low cost, fewer processing steps, high reliability, and the inductance value and Q value of the inductor designed and manufactured by the present invention increase by dozens to hundreds of times. Compared with emerging substrate integrated inductor solutions, the novel inductor of the present invention has excellent performance and better reliability. The processing method of the present invention has low cost, is easy to process and implement, and has high reliability. The high-frequency / radio frequency front-end devices produced according to the method of the present invention will have excellent performance and better reliability. Brief Description of the Drawings

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative efforts.

[0031] Figure 1 FIG. 9 is a schematic structural diagram of an existing discrete inductor device;

[0032] Figure 2 FIG. 13 is a schematic structural diagram of the novel inductor device designed by the present invention.

[0033] In the figure: 1 is the first metal layer, 2 is the second metal layer, 3 is the third metal layer, 4 is the central magnetic core, 5 is the epoxy resin, 11 is the first interlayer via, and 21 is the second interlayer via. Detailed Embodiments

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, rather than all, of the embodiments of the present invention. The description of at least one exemplary embodiment is actually only illustrative and in no way restricts the present invention and its application or use. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0035] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "top", "bottom", etc. is 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 should not be construed as a limitation to 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 or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. Moreover, the terms "first", "second", etc. are used to distinguish similar objects and do not have to be used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein.

[0036] Embodiment 1

[0037] As Figure 2 shown, a novel inductor is characterized in that the inductor includes three metal layers of the same size and a central magnetic core 4; the first metal layer 1, the second metal layer 2, and the third metal layer 3 are stacked in sequence, and an insulating material (epoxy resin) is filled between the metal layers; a first interlayer via 11 and a third interlayer via are respectively provided on the first metal layer 1 and the third metal layer, and two second interlayer vias 21 are provided on the middle second metal layer 2 (one of the second interlayer vias 21 is covered by the first interlayer via 11, and the other second interlayer via 21 covers the third interlayer via, so Figure 2 only the first interlayer via 11 and one of the second interlayer vias 21 are shown in, and the other second interlayer via 21 and the third interlayer via are covered and not shown), and the electrical signal is transmitted to the second interlayer via 21 through the first interlayer via 11 (that is, the electrical signal is transmitted from the first metal layer 1 to the second metal layer 2), and then transmitted to the third interlayer via through the second interlayer via 21 (that is, the electrical signal is transmitted from the second metal layer 2 to the third metal layer 3); the central magnetic core 4 is located at the middle position of each metal layer (the central magnetic core 4 is a solid cylinder formed by processing nickel metal), and the central magnetic core 4 has no electrical connection with each metal layer.

[0038] Preferably, the diameters of the first interlayer via 11, the second interlayer via 21, and the third interlayer via provided above are 40 microns; the diameter of the central magnetic core is set to 70 microns.

[0039] Embodiment 2

[0040] The processing method of the novel inductor described in Embodiment 1 above includes the following steps:

[0041] S1. According to the shape of the first metal layer 1, apply an etching solution to a specified area on the substrate, etch away the excess substrate, and retain the substrate in the shape of the first metal layer 1, thereby forming the first metal layer 1. There is one interlayer via 11 on the first metal layer; the thickness of the substrate is 20 microns.

[0042] S2. Under high temperature and high pressure (using the high temperature and high pressure environment to melt the epoxy resin on the substrate and then bond it to other metal layers), stack a second substrate on the first metal layer 1. One side of this layer of substrate is coated with epoxy resin, and the epoxy resin is bonded to the first metal layer 1. Apply a solution to a specified area on the other side of this layer of substrate, etch away the excess substrate (but the epoxy resin 5 is not etched), forming the second metal layer 2. There are two interlayer vias on the second metal layer, namely two interlayer vias two 21; the substrate is a copper sheet with a thickness of 20 microns, and the thickness of the epoxy resin coated on the substrate is 30 microns.

[0043] S3. Continue under high temperature and high pressure environment, stack a third substrate on the second metal layer 2, and then etch away the excess substrate through the solution to form the third metal layer 3. There is one interlayer via three on the third metal layer.

[0044] S4. Then drill a hole in the epoxy resin, and the drilled hole does not contact each metal layer.

[0045] S5-1. Prepare a cover plate (the cover plate is a steel plate), and process a nickel-plated hole with a diameter of 70 microns on the cover plate. The diameter of the nickel-plated hole is the same as the hole diameter in the above step S4.

[0046] S5-2. Then stack the cover plate on the outermost metal layer (i.e., on the first metal layer 1 or the third metal layer 3), and align the nickel-plated hole completely with the hole drilled in step S4.

[0047] S5-3. Nickel-plate into the hole drilled in step S4 from one side of the cover plate through the nickel-plated hole to form the central magnetic core 4 (the central magnetic core 4 is a solid cylinder formed by nickel plating), that is, the processing of the novel inductor is completed.

[0048] The novel inductor designed and processed by the present invention forms a ferromagnetic magnetic core for a spatial spiral inductor by setting a solid nickel cylinder-shaped central magnetic core. Compared with traditional discrete inductor components, the novel inductor designed by the present invention has low cost, excellent performance, and good reliability. The novel inductor designed and processed by the present invention can increase the inductance value and Q value of the inductor by dozens to hundreds of times.

[0049] The above-mentioned preferred embodiments of the present invention are only used to explain the present invention and are not used to limit the present invention. Any obvious changes or variations derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A novel inductor, characterized in that, the inductor includes N metal layers of the same size and a central magnetic core, and N is a positive integer greater than or equal to 2; wherein, the first metal layer to the Nth metal layer are stacked in sequence and an insulating material is filled between the metal layers; there is a via hole between layers on both the first metal layer and the Nth metal layer, and there are two via holes between layers on the intermediate metal layers, and the electrical signal is transmitted to the metal layer of the next layer through the via hole between layers; the central magnetic core is arranged at the middle position of each metal layer and the central magnetic core has no electrical connection with each metal layer; A method for manufacturing an inductor, comprising the following steps: S1. According to the shape of the first metal layer, apply a chemical solution to a specified area on the substrate and etch away the excess substrate to form the first metal layer and there is a via hole between layers on the first metal layer; S2. Under high temperature and high pressure environments, stack the second substrate on the first metal layer, and one side of this layer of substrate is coated with epoxy resin, the epoxy resin is in contact with the first metal layer, apply a chemical solution to a specified area on the other side of this layer of substrate, and etch away the excess substrate to form the second metal layer and there are two via holes between layers on the second metal layer; S3. Under high temperature and high pressure environments, stack the third substrate on the second metal layer, and one side of this layer of substrate is coated with epoxy resin, the epoxy resin is in contact with the second metal layer, and then apply a chemical solution to a specified area on the other side of this layer of substrate, and etch away the excess substrate to form the third metal layer and there are two via holes between layers on the third metal layer; and so on, repeat the above process, stack the Nth substrate on the (N - 1)th metal layer, and then etch away the excess substrate through the chemical solution to form the Nth metal layer and there is a via hole between layers on the Nth metal layer; S4. Then drill a hole in the epoxy resin, and the drilled hole does not contact each metal layer; S5. Electroplate nickel into the hole opened in step S4 to form the central magnetic core, that is, complete the manufacturing of the novel inductor; The method for manufacturing a novel inductor further includes: S5 - 1. Prepare a cover plate and process a nickel - plating hole on the cover plate, and the diameter of the nickel - plating hole is the same as the hole diameter in step S4; S5 - 2. Stack the cover plate on the outermost metal layer and make the nickel - plating hole completely aligned with the hole opened in step S4; S5 - 3. Electroplate nickel into the hole opened in step S4 from the side of the cover plate through the nickel - plating hole to form the central magnetic core, that is, complete the manufacturing of the novel inductor.

2. A novel inductor according to claim 1, characterized in that, the insulating material is epoxy resin.

3. A novel inductor according to claim 1, characterized in that, the central magnetic core is a solid cylinder formed by nickel processing.

4. A novel inductor according to claim 1, characterized in that, the diameter of the via hole between layers is 40 - 50 μm.

5. A novel inductor according to claim 1, characterized in that, the diameter of the central magnetic core is 60 - 100 μm.

6. A novel inductor according to claim 1, characterized in that, The inductor includes N metal layers of the same size and a central magnetic core, where N is a positive integer greater than or equal to 3.

7. A novel inductor according to claim 1, characterized in that the thickness of the substrate is 10 - 30 μm, and the thickness of the epoxy resin coated on the substrate is 20 - 40 μm.

8. A novel inductor according to claim 1 or 7, characterized in that the substrate is a copper sheet.

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