Integrated copper-iron co-fired inductor capable of realizing multilayer wiring and preparation method of integrated copper-iron co-fired inductor

Abstract

The invention discloses an integrated multi-layer wiring copper-iron co-fired inductor and a preparation method, the integrated multi-layer wiring copper-iron co-fired inductor comprises a first base body, a plurality of isolation points are formed at the upper end of the first base body, a plurality of flat wires are laid among the isolation points, the flat wires comprise L-shaped, U-shaped, linear-shaped and step-shaped flat wires, and the isolation points are arranged on the first base body. The flat wires on the first base body are one or more of an L shape, a U shape, a line shape and a step shape, a third base body is fixed above the first base body, and the first base body and the third base body are of an integrated structure. The two ends of the flat wire extend out of the first base body and the third base body and then are bent to the bottom of the first base body to form pins. Compared with the prior art, a plurality of inductors can be integrated in one package, the consistency of products with the same inductance value is very high, the tolerance is reduced, and the quality of the manufactured inductors is good; and secondly, due to the modular design, the manufacturing difficulty is reduced, and the production efficiency is improved. And thirdly, the mounting area is reduced.

Description

Technical Field

[0001] This invention relates to the field of power inductor technology, and in particular to an integrated, multi-layered wire-compatible copper-iron co-fired inductor and its fabrication method. Background Technology

[0002] Co-fired copper-iron inductors are particularly suitable for operation under high current conditions due to the high permeability and high saturation properties of their material. Furthermore, because the material is prepared through a sintering process, with the powder particles bonded together by an inorganic phase, co-fired copper-iron inductors can operate at high temperatures of 150-180℃ for extended periods. Therefore, co-fired copper-iron inductors are commonly used in the power supply modules of AI computing chips in servers.

[0003] Currently, a single AI computing chip uses a large number of copper-iron co-fired inductors, sometimes more than thirty. Integrating these numerous inductors into a single package can significantly reduce mounting area, and multi-layer wiring can further reduce mounting area. Summary of the Invention

[0004] This invention provides an integrated copper-iron co-fired inductor with multi-layer wiring and its fabrication method, in order to solve the technical problem of occupying mounting area due to the use of a large number of copper-iron co-fired inductors in computing chips.

[0005] This invention provides an integrated, multi-layered copper-iron co-fired inductor, comprising a first substrate, with multiple isolation points formed on the upper end of the first substrate, and multiple flat wires laid between the isolation points. The flat wires include L-shaped, U-shaped, straight, and stepped types. The flat wires on the first substrate are one or more of L-shaped, U-shaped, straight, and stepped types. A third substrate is fixed above the first substrate, and the first substrate and the third substrate are an integral structure. Both ends of the flat wires extend beyond the first substrate and the third substrate and then bend to the bottom of the first substrate to form pins.

[0006] Preferably, the height of the isolation point is greater than the thickness of the flat line.

[0007] Preferably, the isolation point is cylindrical.

[0008] Preferably, a second substrate is provided between the first substrate and the third substrate. The second substrate has clearance holes adapted to the isolation points. The flat line is laid between the isolation points on the second substrate. Both ends of the flat line on the second substrate extend beyond the second substrate and the third substrate and then bend to the bottom of the first substrate to form pins. The type of the flat line on the second substrate is one or more of L-shaped, U-shaped, straight, and stepped. The first substrate, the second substrate, and the third substrate are an integral structure.

[0009] Preferably, the first substrate, the second substrate, and the third substrate are all rectangular.

[0010] Preferably, the first substrate, the second substrate, and the third substrate constitute a cuboid or a cube.

[0011] This invention provides a method for fabricating the above-described integrated, multilayer-wireable copper-iron co-fired inductor, comprising the following steps:

[0012] S1: Cold press the granulated magnetic powder under a pressure of 300-600MPa for 6-10 seconds to obtain the first matrix;

[0013] S2: Install a flat wire between isolation points on the first substrate, wherein the two leads of the flat wire are located at the bottom of the first substrate;

[0014] S3: A layer of magnetic granulation powder is spread on the first substrate, and then a blank is obtained by hot pressing.

[0015] S4: After sintering the blank, a layer of tin is electroplated on the pins;

[0016] The flat lines include L-shaped, U-shaped, straight, and stepped types, and the flat lines laid on the first substrate are one or more of L-shaped, U-shaped, straight, and stepped types.

[0017] Preferably, the steps following step S2 and before step S3 are further included:

[0018] S01: The magnetic sheet mixture is mixed and stirred with Triton to obtain a first mixture, the viscosity of the first mixture is 2000-4000, and the magnetic sheet mixture contains the same types of materials as the magnetic granulated powder.

[0019] S02: The first mixture is cast into a 50-100μm thick magnetic film above the first substrate, with the upper end of the isolation point exposed outside the magnetic film. A silicone mold is used to press the magnetic film to the first substrate with a pressure of 1-5MPa. The pressed magnetic film becomes the second substrate above the first substrate.

[0020] S03: Install a flat wire between the isolation points on the second substrate, wherein the two pins of the flat wire on the second substrate are located at the bottom of the first substrate;

[0021] Among them, the type of flat line on the second substrate is one or more of L-shaped, U-shaped, straight, and stepped;

[0022] The corresponding step S3 is: a layer of magnetic granulation powder is spread on the second substrate, and then a blank is obtained by hot pressing.

[0023] Preferably, the flat lines include L-shaped, U-shaped, straight, and stepped types, with the flat lines on the first substrate being one or more of L-shaped, U-shaped, straight, and stepped types, and the flat lines on the second substrate being one or more of L-shaped, U-shaped, straight, and stepped types.

[0024] Preferably, the preparation steps of the magnet granulated powder are as follows: using iron-silicon-aluminum and iron-nickel atomized powder coated with silicon dioxide or aluminum oxide as the first raw material, the powder diameter of the first raw material is 5μm, the first raw material is mixed with 0.5-3wt% silicone resin and 8-15wt% acetone and stirred into wet clay blocks, and then the wet clay blocks are granulated and dried through a 40-60 mesh sieve to obtain magnet granulated powder.

[0025] Preferably, the manufacturing steps of the magnetic sheet mixture are as follows: using sheet-like iron-silicon-aluminum and iron-nickel atomized powder coated with silicon dioxide or aluminum oxide as the second raw material, wherein the diameter of the sheet-like powder in the second raw material is 4-10 μm and the thickness is 0.4-1 μm, and mixing the second raw material with 7-12 wt% silicone resin and 8-15 wt% acetone to obtain the magnetic sheet mixture.

[0026] Compared with existing technologies, this invention uses a flat magnetic core with many isolation points arrayed as the first substrate. Flat wires are routed around the isolation points, and the shape of the flat wires is determined according to the required inductance value. After assembling the flat wires, they are filled with powder and flattened again. If it is a multi-layer wiring, after laying the first layer of flat wires, a layer of magnetic powder film is cast on the first substrate using a casting process. The magnetic powder in the casting paste is flake-shaped magnetic powder, which increases the filling rate and enhances the isolation between the two layers of flat wires. Finally, it is filled with powder again and hot-pressed flattened. Through this structural design, it is convenient to integrate multiple inductors into one package, and the consistency of products with the same inductance value is very high, the tolerance is reduced, and the quality of the manufactured inductors is good. Secondly, the modular design means that for various required inductance values, only the shape of the flat wires needs to be changed, without the need for separate design, which reduces the manufacturing difficulty and improves production efficiency. Thirdly, it reduces the mounting area. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the structure for laying flat lines in this invention;

[0029] Figure 2 for Figure 1 Top view;

[0030] Figure 3 A structural schematic diagram of laying flat lines according to another perspective of the present invention;

[0031] Figure 4 This is a schematic diagram of the structure of Embodiment 1 of the present invention;

[0032] Figure 5 This is a schematic diagram of the structure of the first substrate of the present invention;

[0033] Figure 6 This is a schematic diagram of the structure for laying the first layer of flat lines in Embodiment 2 of the present invention;

[0034] Figure 7 This is a schematic diagram of the structure for installing the second substrate in Embodiment 2 of the present invention;

[0035] Figure 8 This is a schematic diagram of the structure for laying the second layer of flat lines in Embodiment 2 of the present invention;

[0036] Figure 9 This is a schematic diagram of the structure of Embodiment 2 of the present invention.

[0037] Figure label:

[0038] 1. First substrate, 2. Second substrate, 3. Third substrate, 4. Flat line, 5. Pin, 11. Isolation point, 41. L-shaped, 42. U-shaped, 43. Linear, 44. Stepped. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0040] See attached document Figure 1 and attached Figure 4 An integrated, multi-layered, co-fired copper-iron inductor includes a first substrate 1. Multiple isolation points 11 are formed at the upper end of the first substrate 1, and the isolation points 11 are evenly distributed within the first substrate 1. Multiple flat wires 4 are laid between the isolation points 11. (See attached diagram.) Figure 2The types of flat lines 4 include: L-shaped 41, U-shaped 42, straight 43, and stepped 44. The flat lines 4 on the first substrate 1 are one or more of the following types: L-shaped 41, U-shaped 42, straight 43, and stepped 44. A third substrate 3 is fixed above the first substrate 1. The first substrate 1 and the third substrate 3 are an integral structure. (See attached diagram.) Figure 3 Both ends of the flat line 4 extend beyond the first substrate 1 and the third substrate 3, then bend to the bottom of the first substrate 1 to form pins 5. In this invention, the flat line 4 is routed between isolation points 11. The routing of the flat line 4 is determined according to the required inductance value. This structural design facilitates the integration of multiple inductors of the same type in one package (copper-iron co-fired inductor), and also facilitates the integration of inductors of different types in one package. Through this modular design, for various required inductance values, only the routing of the flat line needs to be changed, without the need for separate design, reducing manufacturing difficulty and improving production efficiency. Secondly, inductors with the same inductance value can achieve high consistency, with smaller tolerances, resulting in high-quality inductors. Thirdly, it reduces the mounting area.

[0041] Specifically, the isolation points 11 are evenly distributed on the first substrate 1. This structural design makes it easier to lay flat lines 4 between the isolation points 11.

[0042] Specifically, when the flat lines 4 are distributed in a U-shape 42 at the upper end of the first substrate 1, the two ends of the flat lines 4 are located on the same side of the first substrate 1. When the flat lines 4 are distributed in an L-shape 41 at the upper end of the first substrate 1, the two ends of the flat lines 4 are located on adjacent sides of the first substrate 1. When the flat lines 4 are a straight line at the upper end of the first substrate 1, the two ends of the flat lines 4 are located on opposite sides of the first substrate 1. When the flat lines 4 are distributed in a stepped shape 44 at the upper end of the first substrate 1, the two ends of the flat lines 4 are located on opposite sides of the first substrate 1.

[0043] In another embodiment of the present invention, the height of the isolation point 11 is greater than the thickness of the flat line 4.

[0044] As another embodiment of the present invention: the isolation point 11 is cylindrical or cuboid, and the shape of the isolation point 11 can satisfy the routing of the flat line 4.

[0045] Specifically, flat line 4 is a flat copper wire.

[0046] In another embodiment of the present invention: a second substrate 2 is provided between the first substrate 1 and the third substrate 3. The second substrate 2 has clearance holes adapted to the isolation points 11. A flat line 4 is laid between the isolation points 11 on the second substrate 2. Both ends of the flat line 4 on the second substrate 2 extend beyond the second substrate 2 and the third substrate 3 and then bend to the bottom of the first substrate 1 to form a pin 5. The type of the flat line 4 on the second substrate 2 is one or more of L-shaped 41, U-shaped 42, straight 43, and stepped 44. The first substrate 1, the second substrate 2, and the third substrate 3 are an integral structure. By adding a substrate and laying a layer of flat line 4, this structural design makes it easy to set up multiple layers of flat line 4, and can further reduce the mounting area while integrating multiple inductors.

[0047] In another embodiment of the present invention, the first substrate 1, the second substrate 2 and the third substrate 3 are all rectangular.

[0048] Another implementation of the first substrate 1: Refer to Appendix Figure 5 The first substrate 1 has a mounting hole in the middle. Correspondingly, if the copper-iron co-fired inductor is two layers, the second substrate 2 and the third substrate 3 also have mounting holes in the middle. The mounting holes can accommodate other chip mounting.

[0049] As another embodiment of the present invention: refer to the appendix Figure 9 The first substrate 1, the second substrate 2, and the third substrate 3 form a cuboid or cube.

[0050] This invention provides a method for fabricating the above-mentioned integrated, multilayer-wireable copper-iron co-fired inductor, comprising the following steps:

[0051] S1: The magnetic granulated powder is cold-pressed in a mold under a pressure of 300-600MPa for 6-10 seconds to obtain the first matrix 1;

[0052] S2: See Appendix Figure 6 A flat line 4 is installed between isolation points 11 on the first substrate 1, and the two pins 5 of the flat line 4 are located at the bottom of the first substrate 1;

[0053] S3: A layer of magnetic granulation powder is spread on the first substrate 1, and then a blank is obtained by hot pressing.

[0054] S4: After sintering the blank, a layer of tin is electroplated on pin 5.

[0055] In step S2, the flat line 4 includes the following types: L-shaped 41, U-shaped 42, straight 43, and stepped 44. The flat line 4 laid on the first substrate 1 is one or more of these types. This invention uses the substrate as a base plate, and the flat line 4 is laid along the isolation points 11. The laying arrangement of the flat line 4 between the isolation points 11 is determined according to the required sensitivity value, thus providing a modular design scheme. It eliminates the need for separate design for different sensitivity values, reducing manufacturing difficulty.

[0056] The steps following step S2 and before step S3 include the following:

[0057] S01: The magnetic sheet mixture is mixed and stirred with Triton to obtain a first mixture. The viscosity of the first mixture is 2000-4000. The magnetic sheet mixture contains the same types of materials as the magnetic granulated powder.

[0058] S02: Refer to Appendix Figure 7 The first mixture is cast into a 50-100μm thick magnetic film above the first substrate 1, with the upper end of the isolation point 11 exposed outside the magnetic film. A silicone mold is used to press the magnetic film to the first substrate 1 with a pressure of 1-5MPa. The pressed magnetic film becomes the second substrate 2 above the first substrate 1. In this design, a layer of magnetic powder film is cast on the first substrate 1 to form the second substrate 2. The magnetic powder in the casting slurry is a sheet-like magnetic powder, which improves the filling rate between the isolation points 11 and enhances the isolation between the two layers of flat lines 4.

[0059] S03: Refer to Appendix Figure 8 Flat wires 4 are installed between isolation points 11 on the second substrate 2. The two pins 5 of the flat wires 4 on the second substrate 2 are located at the bottom of the first substrate 1. All pins 5 of the flat wires 4 are located at the bottom of the first substrate 1 for easy mounting.

[0060] Among them, the flat line 4 laid on the second substrate 2 is one or more of the following types: L-shaped 41, U-shaped 42, straight 43, and stepped 44;

[0061] When laying two layers of flat lines 4, the corresponding step S3 is: to lay a layer of magnetic granulation powder on the second substrate 2, and then obtain the blank by hot pressing.

[0062] As another embodiment of the present invention, the preparation steps of the magnet granulated powder are as follows: using iron-silicon-aluminum and iron-nickel atomized powders coated with silicon dioxide or aluminum oxide as the first raw material, the powder diameter of the first raw material is 5μm, the first raw material is mixed with 0.5-3wt% silicone resin and 8-15wt% acetone and stirred into wet clay blocks, and then the wet clay blocks are granulated and dried through a 40-60 mesh sieve to obtain magnet granulated powder.

[0063] As another embodiment of the present invention, the preparation steps of the magnetic sheet mixture are as follows: using sheet-like iron-silicon-aluminum and iron-nickel atomized powder coated with silicon dioxide or aluminum oxide as the second raw material, wherein the diameter of the sheet-like powder in the second raw material is 4-10 μm and the thickness is 0.4-1 μm, and mixing the second raw material with 7-12 wt% silicone resin and 8-15 wt% acetone to obtain the magnetic sheet mixture.

[0064] Another method for producing magnet granulated powder: Mix the first raw material with 0.5-3wt% silicone resin and anhydrous ethanol to form wet clay blocks, then granulate the wet clay blocks through a 40-60 mesh sieve and dry them to obtain magnet granulated powder.

[0065] In step S01, the magnetic sheet mixture is mixed and stirred with 0.5-2.0 wt% of Triton to obtain a first mixture.

[0066] In step S02, the magnet film is air-dried, and then the air-dried magnet film is cut according to the size of the first substrate 1 and then pressed.

[0067] In step S3, the hot pressing method of the copper-iron co-fired inductor with a layer of flat wire 4 includes the following steps: the first substrate 1 with a layer of magnetic granulated powder is placed in the mold cavity. Before pressing, the mold cavity is preheated at 110-130℃ for 60 seconds. Then, it is pressed at 600-1800MPa pressure and 160-180℃ for 70-90 seconds. Then, it is demolded to obtain the formed blank.

[0068] The hot pressing method for the copper-iron co-fired inductor with two layers of flat wire 4 includes the following steps: the second substrate 2, which is coated with a layer of magnetic granulated powder, is placed in the mold cavity. Before pressing, the mold cavity is preheated at 110-130℃ for 60 seconds, and then pressed at 600-1800MPa pressure and 160-180℃ for 70-90 seconds. Then, the molded blank is obtained by demolding.

[0069] In step S4, the formed blank is placed in an atmosphere furnace and sintered at 660-720℃ for 1-2 hours under nitrogen protection. After cooling, the blank is removed and a layer of tin is electroplated on the exposed pin 5 surface.

[0070] The following copper-iron co-fired inductor was prepared using the above method:

[0071] The first substrate 1 of the copper-iron co-fired inductor has a flat plate thickness of 0.7mm, a cylinder diameter of 2mm, a cylinder spacing of 2mm, an outermost cylinder 1mm from the edge of the flat plate, and a cylinder height of 0.5mm (the cylinder height is designed according to the number of wiring layers; for one layer of wiring, the cylinder height is 0.5mm, and for two layers of wiring, the cylinder height is 1mm). The flat wire 4 is 0.35mm thick and 2mm wide, and the flat wire 4 is laid in a U-shape 42. The flat wire 4 only surrounds one cylinder. After assembly, the total thickness after filling with powder and flattening is 1.5mm. The inductance value of this inductor is measured to be 120nH.

[0072] Based on the above parameters, a first substrate 1 with 3×21 cylinders is prepared. 20 flat wires 4 are laid on the first substrate 1, with each flat wire 4 surrounding a cylinder. The resulting copper-iron co-fired inductor has an inductance range of less than 5% (the smaller the range, the better), which is much lower than the 15-20% inductance range distribution of ordinary single inductors.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An integrated, multi-layer wiring-enabled copper-iron co-fired inductor, characterized in that, The system includes a first substrate, with multiple isolation points formed on the upper end of the first substrate. Multiple flat lines are laid between the isolation points. The flat lines are of the following types: L-shaped, U-shaped, straight, and stepped. The flat lines on the first substrate are of one or more of the following types: L-shaped, U-shaped, straight, and stepped. A third substrate is fixed above the first substrate. The first substrate and the third substrate are an integral structure. Both ends of the flat lines extend beyond the first substrate and the third substrate and then bend to the bottom of the first substrate to form pins.

2. The integrated, multi-layer wiring-capable copper-iron co-fired inductor according to claim 1, characterized in that, The height of the isolation point is greater than the thickness of the flat line.

3. The integrated, multi-layer wiring-capable copper-iron co-fired inductor according to claim 2, characterized in that, The isolation point is cylindrical.

4. The integrated, multi-layer wiring-capable copper-iron co-fired inductor according to claim 3, characterized in that, A second substrate is provided between the first substrate and the third substrate. The second substrate has clearance holes adapted to the isolation points. The flat line is laid between the isolation points on the second substrate. Both ends of the flat line on the second substrate extend beyond the second substrate and the third substrate and then bend to the bottom of the first substrate to form pins. The type of the flat line on the second substrate is one or more of L-shaped, U-shaped, straight, and stepped. The first substrate, the second substrate, and the third substrate are an integral structure.

5. The integrated, multi-layer wiring-enabled copper-iron co-fired inductor according to claim 4, characterized in that, The first, second, and third substrates are all rectangular.

6. The integrated, multi-layer wiring-enabled copper-iron co-fired inductor according to claim 5, characterized in that, The first substrate, the second substrate, and the third substrate constitute a cuboid or a cube.

7. A method for fabricating an integrated, multi-layered wiring-capable copper-iron co-fired inductor as described in any one of claims 1-6, characterized in that, Includes the following steps: S1: Cold press the granulated magnetic powder under a pressure of 300-600MPa for 6-10 seconds to obtain the first matrix; S2: Install a flat wire between isolation points on the first substrate, wherein the two leads of the flat wire are located at the bottom of the first substrate; S3: A layer of magnetic granulation powder is spread on the first substrate, and then a blank is obtained by hot pressing. S4: After sintering the blank, a layer of tin is electroplated on the pins; The types of flat lines laid on the first substrate include L-shaped, U-shaped, straight, and stepped types. The flat lines on the first substrate are one or more of the following types: L-shaped, U-shaped, straight, and stepped.

8. The preparation method according to claim 7, characterized in that, The steps following step S2 and before step S3 include the following steps: S01: The magnetic sheet mixture is mixed and stirred with Triton to obtain a first mixture, the viscosity of the first mixture is 2000-4000, and the magnetic sheet mixture contains the same types of materials as the magnetic granulated powder. S02: The first mixture is cast into a 50-100μm thick magnetic film above the first substrate, with the upper end of the isolation point exposed outside the magnetic film. A silicone mold is used to press the magnetic film to the first substrate with a pressure of 1-5MPa. The pressed magnetic film becomes the second substrate above the first substrate. S03: Install a flat wire between the isolation points on the second substrate, wherein the two pins of the flat wire on the second substrate are located at the bottom of the first substrate; Among them, the type of flat line on the second substrate is one or more of L-shaped, U-shaped, straight, and stepped; The corresponding step S3 is: a layer of magnetic granulation powder is spread on the second substrate, and then a blank is obtained by hot pressing.

9. The preparation method according to claim 8, characterized in that, The steps for preparing the magnet granulated powder are as follows: using iron-silicon-aluminum and iron-nickel atomized powders coated with silicon dioxide or aluminum oxide as the first raw material, the powder diameter of the first raw material is 5μm, mixing the first raw material with 0.5-3wt% silicone resin and 8-15wt% acetone to form wet clay blocks, and then granulating and drying the wet clay blocks through a 40-60 mesh sieve to obtain magnet granulated powder.

10. The preparation method according to claim 9, characterized in that, The preparation steps of the magnetic sheet mixture are as follows: using sheet-like iron-silicon-aluminum and iron-nickel atomized powder coated with silicon dioxide or aluminum oxide as the second raw material, wherein the diameter of the sheet-like powder in the second raw material is 4-10 μm and the thickness is 0.4-1 μm, and mixing the second raw material with 7-12 wt% silicone resin and 8-15 wt% acetone to obtain the magnetic sheet mixture.

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