Low-loss chip inductor and preparation method and application thereof

Abstract

The invention discloses a low-loss chip inductor and a preparation method and application thereof, and relates to the technical field of electronic devices, and the preparation method comprises the following steps: stamping and bending a copper sheet into an n-shaped material sheet; putting the n-shaped material sheet into a mold, filling magnetic powder, and pressing for a first preset time at a preset pressing pressure and a preset pressing temperature to obtain a molded inductor; sintering the molded inductor at a preset sintering temperature and a preset gas atmosphere for a second preset time to obtain a sintered inductor; spraying paint on the sintered inductor, cutting the side wall of the sintered inductor, and leading out a terminal; removing the residual paint liquid on the terminal to expose the terminal; electroplating a copper-nickel-tin layer on the terminal to obtain a low-loss chip inductor; the technical problems that an iron-based alloy powder chip inductor adopting the design that a single copper sheet is directly led out and then bent is adopted, the effective magnetic circuit area is small, the leakage flux is large, and the electromagnetic performance is affected can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic devices, and in particular to a low-loss chip inductor and a preparation method and application thereof. Background Art

[0002] Iron-based alloy powder chip inductor is a chip inductor with a core made of soft magnetic metal materials such as alloys. It is a key component of the chip power supply module and provides power for the front end of chips such as GPUs and CPUs.

[0003] Currently, the design of iron-based alloy powder inductors uses a single copper sheet as the lead, which is then bent twice to optimize the inductor's magnetic field distribution and achieve flexible layout within a limited space. However, this design has many disadvantages. For example, the effective magnetic circuit area is very small and there is a large amount of leakage flux, which greatly reduces the electromagnetic performance of the inductor and has a significant radiation impact on surrounding chips and other devices. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a low-loss chip inductor and its preparation method and application, aiming to solve the technical problems that the iron-based alloy powder chip inductor with a single copper sheet directly led out and then bent has a small effective magnetic circuit area and large leakage flux, which affects the electromagnetic performance.

[0005] A first aspect of the present invention is to provide a method for preparing a low-loss chip inductor, the method comprising:

[0006] Stamping and bending a copper sheet into a "J"-shaped sheet, wherein the "J"-shaped sheet comprises a U-shaped portion and terminals respectively provided at both ends of the U-shaped portion;

[0007] Placing the several types of sheets into a mold, filling in magnetic powder, and pressing at a preset pressing pressure and a preset pressing temperature for a first preset time to obtain a molded inductor;

[0008] sintering the molded inductor at a preset sintering temperature and a preset gas atmosphere for a second preset time to obtain a sintered inductor;

[0009] spraying paint on the sintered inductor, cutting the sidewalls of the sintered inductor, and leading out the terminals;

[0010] removing the remaining paint liquid on the terminals to expose the terminals;

[0011] A copper-nickel-tin layer is electroplated on the terminal to obtain a low-loss chip inductor.

[0012] Compared with the prior art, the beneficial effect of the present invention is that: a preparation method of a low-loss chip inductor provided by the present invention comprises: punching and bending a copper sheet into a "J"-shaped sheet, placing the "J"-shaped sheet into a mold, filling it with magnetic powder, and pressing it at a preset pressing pressure and a preset pressing temperature for a first preset time to obtain a molded inductor, wherein the "J"-shaped sheet is completely buried in the magnet, forming a completely shielded structure, which can shield external devices and reduce interference from external devices, has excellent magnetic circuit characteristics, and greatly improves DC bias capability and inductance. Compared with a direct lead-out terminal structure design, it has less leakage magnetic flux, which will reduce the loss of the low-loss chip inductor, thereby solving the technical problem that the iron-based alloy powder chip inductor using a single copper sheet direct lead-out and then bending design has a small effective magnetic circuit area and large leakage magnetic flux, which affects the electromagnetic performance.

[0013] According to one aspect of the above technical solution, the length of the copper sheet is 10 mm to 14 mm, the width is 2 mm to 3 mm, and the thickness of the copper sheet is 0.3 mm to 0.8 mm.

[0014] According to one aspect of the above technical solution, the copper sheet is stamped and bent into several-shaped sheets using a cold rolling process, and the bending angles of the several-shaped sheets are all 80°~100°. The length of the terminal is 0.4mm~0.6mm, and the length of the U-shaped portion on the side away from the terminal is 5mm~9mm.

[0015] According to one aspect of the above technical solution, the magnetic powder includes one or a mixture of iron silicon, iron silicon chromium, iron silicon aluminum, and iron nickel.

[0016] According to one aspect of the above technical solution, the preset pressing pressure is 15T to 25T, the preset pressing temperature is 160°C to 200°C, and the first preset time is 12s to 18s.

[0017] According to one aspect of the above technical solution, the preset sintering temperature is 700° C. to 850° C., and the second preset time is 50 min to 70 min.

[0018] According to one aspect of the above technical solution, the preset gas atmosphere is a nitrogen and hydrogen atmosphere, and the gas flow ratio of nitrogen to hydrogen is (1-3):1.

[0019] According to one aspect of the above technical solution, the mold includes a columnar mold or a block mold.

[0020] A second aspect of the present invention is to provide a low-loss chip inductor prepared by the above-mentioned method for preparing a low-loss chip inductor.

[0021] The third aspect of the present invention is to provide the application of a low-loss chip inductor prepared by the above-mentioned method for preparing a low-loss chip inductor in AI servers and super computing power core devices for stable current power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0023] Figure 1 This is a flowchart of a method for preparing a low-loss chip inductor according to the present invention;

[0024] Figure 2 Schematic diagram of the structure of the low-loss chip inductor in the present invention;

[0025] Description of main component symbols:

[0026] Low-loss chip inductor 1, several types of chips 2, terminals 20. DETAILED DESCRIPTION

[0027] To make the objectives, features, and advantages of the present invention more readily apparent, the following detailed description of specific embodiments of the present invention is provided in conjunction with the accompanying drawings. The accompanying drawings illustrate several embodiments of the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present invention.

[0028] See also Figure 1-Figure 2 , which shows a method for preparing a low-loss chip inductor provided by the present invention, the preparation method includes steps S10-S15:

[0029] Step S10, punching and bending a copper sheet into a U-shaped sheet, wherein the U-shaped sheet includes a U-shaped portion and terminals respectively provided at both ends of the U-shaped portion;

[0030] The length of the copper sheet is 10 mm to 14 mm, the width is 2 mm to 3 mm, and the thickness of the copper sheet is 0.3 mm to 0.8 mm.

[0031] Furthermore, the copper sheet is stamped and bent into a "J"-shaped sheet using a cold rolling process, the bending angles of the "J"-shaped sheets are all 80° to 100°, the length of the terminal is 0.4mm to 0.6mm, and the length of the U-shaped portion on the side away from the terminal is 5mm to 9mm.

[0032] It should be noted that if Figure 2As shown, the sheet material 2 is completely buried in the magnet of the low-loss chip inductor 1, which is a completely shielded structure. It can shield external devices and reduce interference from external devices. It has excellent magnetic circuit characteristics and greatly improves the DC bias capability and inductance. Compared with the direct lead-out terminal structure design, it has less leakage magnetic field, which will reduce the loss of the low-loss chip inductor 1.

[0033] Step S11, placing the several types of sheets into a mold, filling in magnetic powder, and pressing at a preset pressing pressure and a preset pressing temperature for a first preset time to obtain a molded inductor;

[0034] The magnetic powder includes one or a mixture of iron silicon, iron silicon chromium, iron silicon aluminum and iron nickel.

[0035] In order to increase the density of the low-loss chip inductor 1 , high-pressure pressing is required.

[0036] Preferably, the preset pressing pressure is 15T to 25T, for example, 15T, 18T, 20T, 22T or 25T, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0037] Preferably, the preset pressing temperature is 160°C to 200°C, for example, 160°C, 170°C, 180°C, 190°C or 200°C, but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

[0038] Preferably, the first preset time is 12s to 18s, for example, 12s, 15s or 18s, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0039] Furthermore, in order to improve the pressing efficiency, a large-tonnage servo pressing machine is used to solve the multi-hole pressing problem.

[0040] The mold, which can be cylindrical or block-shaped, exhibits excellent shielding properties. The low-loss chip inductor 1, after compaction and sintering using a cylindrical mold, exhibits a superior magnetic circuit structure, further reducing losses within the low-loss chip inductor 1. Furthermore, the cylindrical mold can reduce the amount of magnetic powder used, thus reducing costs.

[0041] Furthermore, the diameter of the columnar mold is 7mm to 9mm, and the height is 7mm to 9mm; the length of the block mold is 7mm to 9mm, and the height is 7mm to 9mm.

[0042] Step S12, sintering the molded inductor at a preset sintering temperature and a preset gas atmosphere for a second preset time to obtain a sintered inductor;

[0043] In this embodiment, the use of copper-iron co-firing technology can effectively reduce the total loss of the terminal product and improve the conversion efficiency. This is because the co-sintering of alloy powder will improve the DC bias capability of the low-loss chip inductor 1, allowing large current to pass through, thereby providing a new alternative for high-current scenarios such as servers and AI servers.

[0044] Preferably, the preset sintering temperature is 700° C. to 850° C., for example, 700° C., 750° C. or 850° C., but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0045] Preferably, the second preset time is 50 minutes to 70 minutes, for example, it can be 50 minutes, 55 minutes, 60 minutes, 65 minutes or 70 minutes, but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0046] Preferably, the preset gas atmosphere is a nitrogen and hydrogen atmosphere, and the gas flow ratio of nitrogen to hydrogen is (1-3):1.

[0047] Step S13, spraying paint on the sintered inductor, cutting the sidewalls of the sintered inductor, and leading out the terminals;

[0048] The paint is sprayed to prevent the low-loss chip inductor 1 from rusting.

[0049] Furthermore, the terminal 20 is an interface for connecting the low-loss chip inductor 1 to an external circuit.

[0050] Step S14, removing the remaining paint liquid on the terminals to expose the terminals;

[0051] Step S15: electroplating a copper-nickel-tin layer on the terminal to obtain a low-loss chip inductor.

[0052] Here, the electrodes are formed by electroplating.

[0053] In addition, the present invention also provides a low-loss chip inductor prepared by the above-mentioned method for preparing a low-loss chip inductor.

[0054] In addition, the present invention also provides the application of low-loss chip inductors prepared by the above-mentioned method for preparing low-loss chip inductors in AI servers and super computing power core devices for stable current power supply.

[0055] The present invention is further described below with specific examples:

[0056] Example 1

[0057] A first embodiment of the present invention provides a method for preparing a low-loss chip inductor, the method comprising steps S10-S15:

[0058] Step S10, punching and bending a copper sheet into a U-shaped sheet, wherein the U-shaped sheet includes a U-shaped portion and terminals respectively provided at both ends of the U-shaped portion;

[0059] The length of the copper sheet is 12 mm, the width of the copper sheet is 2 mm, and the thickness of the copper sheet is 0.8 mm.

[0060] Furthermore, the copper sheet is stamped and bent into a "J"-shaped sheet by a cold rolling process, and the bending angles of the "J"-shaped sheets are all 90°. The length of the terminal is 0.5 mm, and the length of the U-shaped portion on the side away from the terminal is 7 mm.

[0061] Step S11, placing the several types of sheets into a mold, filling in magnetic powder, and pressing at a preset pressing pressure and a preset pressing temperature for a first preset time to obtain a molded inductor;

[0062] The magnetic powder includes one or a mixture of iron silicon, iron silicon chromium, iron silicon aluminum and iron nickel.

[0063] In order to increase the density of low-loss chip inductors, high-pressure pressing is required.

[0064] Preferably, the preset pressing pressure is 20T, the preset pressing temperature is 180°C, and the first preset time is 15s.

[0065] The mold is a columnar mold.

[0066] The cylindrical mold has a diameter of 8 mm and a height of 8 mm.

[0067] Step S12, sintering the molded inductor at a preset sintering temperature and a preset gas atmosphere for a second preset time to obtain a sintered inductor;

[0068] The preset sintering temperature is 700° C., the second preset time is 60 minutes, the preset gas atmosphere is a nitrogen and hydrogen atmosphere, and the gas flow ratio of nitrogen to hydrogen is 2:1.

[0069] Step S13, spraying paint on the sintered inductor, cutting the sidewalls of the sintered inductor, and extracting terminals;

[0070] Step S14, removing the remaining paint liquid on the terminals to expose the terminals;

[0071] Step S15: electroplating a copper-nickel-tin layer on the terminal to obtain a low-loss chip inductor.

[0072] Example 2

[0073] A second embodiment of the present invention provides a method for manufacturing a low-loss chip inductor. The method for manufacturing the low-loss chip inductor in this embodiment differs from the method for manufacturing the low-loss chip inductor in the first embodiment in that:

[0074] The mold is a block mold.

[0075] The block mold has a length of 8 mm and a height of 8 mm.

[0076] Comparative Example 1

[0077] The first comparative example of the present invention provides a method for preparing a low-loss chip inductor. The method for preparing the low-loss chip inductor in this comparative example differs from the method for preparing the low-loss chip inductor in the first embodiment in that:

[0078] Traditionally, a single copper sheet is directly led out and then folded twice. The length of the copper sheet is 12mm and the thickness is 0.8mm.

[0079] Comparative Example 2

[0080] A second comparative example of the present invention provides a method for preparing a low-loss chip inductor. The method for preparing the low-loss chip inductor in this comparative example differs from the method for preparing the low-loss chip inductor in the first embodiment in that:

[0081] Traditionally, a single copper sheet is directly led out and then folded twice. The length of the copper sheet is 12 mm and the thickness is 0.8 mm. The mold is a block mold.

[0082] Please refer to Table 1 below, which shows the performance test results of low-loss chip inductors prepared under different embodiments and comparative examples.

[0083] Table 1

[0084]

[0085] It should be noted that the loss test method is to test the loss power per unit volume (per cubic centimeter) of the low-loss chip inductor under the conditions of a magnetic induction intensity of 50mT and a frequency of 100kHz; the anti-saturation performance test method is to test the percentage of inductance decrease compared to the initial value when a current of 80A passes through the low-loss chip inductor, reflecting the DC bias capability.

[0086] According to the data in Table 1, by punching and bending the copper sheet into a "J"-shaped sheet and completely burying the "J"-shaped sheet in the magnet, the DC bias capability and inductance can be greatly improved, and the loss of the low-loss chip inductor can be reduced.

[0087] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0088] The above-described embodiments merely illustrate several implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A method for preparing a low-loss chip inductor, characterized in that: The preparation method comprises: Stamping and bending a copper sheet into a "J"-shaped sheet, wherein the "J"-shaped sheet comprises a U-shaped portion and terminals respectively provided at both ends of the U-shaped portion; Placing the several types of sheets into a mold, filling in magnetic powder, and pressing at a preset pressing pressure and a preset pressing temperature for a first preset time to obtain a molded inductor; sintering the molded inductor at a preset sintering temperature and a preset gas atmosphere for a second preset time to obtain a sintered inductor; spraying paint on the sintered inductor, cutting the sidewall of the sintered inductor, and leading out the terminals; removing the remaining paint liquid on the terminals to expose the terminals; A copper-nickel-tin layer is electroplated on the terminal to obtain a low-loss chip inductor.

2. The method for preparing a low-loss chip inductor according to claim 1, wherein: The length of the copper sheet is 10 mm to 14 mm, the width is 2 mm to 3 mm, and the thickness of the copper sheet is 0.3 mm to 0.8 mm.

3. The method for preparing a low-loss chip inductor according to claim 2, wherein: The copper sheet is stamped and bent into several-shaped sheets using a cold rolling process. The bending angles of the several-shaped sheets are all 80° to 100°. The length of the terminal is 0.4mm to 0.6mm, and the length of the U-shaped portion on the side away from the terminal is 5mm to 9mm.

4. The method for preparing a low-loss chip inductor according to claim 1, wherein: The magnetic powder includes one or a mixture of iron silicon, iron silicon chromium, iron silicon aluminum and iron nickel.

5. The method for preparing a low-loss chip inductor according to claim 4, wherein: The preset pressing pressure is 15T to 25T, the preset pressing temperature is 160°C to 200°C, and the first preset time is 12s to 18s.

6. The method for preparing a low-loss chip inductor according to claim 1, wherein: The preset sintering temperature is 700° C. to 850° C., and the second preset time is 50 min to 70 min.

7. The method for preparing a low-loss chip inductor according to claim 6, wherein: The preset gas atmosphere is a nitrogen and hydrogen atmosphere, and the gas flow ratio of nitrogen to hydrogen is (1-3):

1.

8. The method for preparing a low-loss chip inductor according to claim 1, wherein: The mold includes a columnar mold or a block mold.

9. A low-loss chip inductor prepared by the method for preparing a low-loss chip inductor according to any one of claims 1 to 8.

10. An application of a low-loss chip inductor prepared by the method for preparing a low-loss chip inductor as described in any one of claims 1 to 8 in providing stable current and power supply in AI servers and super computing power core devices.

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