CN103377795A - Electromagnetic device and manufacturing method thereof - Google Patents

Abstract

The present invention discloses an electromagnetic device, which comprises a coil unit having a multi-layer stacking structure; a molded body covering the coil unit; and two electrodes electrically coupled to two ends of the coil unit respectively, wherein the coil unit is made by using an electroplating lamination process or a pressing technology.

Description

Electromagnetic device and manufacturing method thereof

technical field

The invention relates to an electromagnetic device, in particular to a surface-mounting electromagnetic device.

Background technique

As is known to those skilled in the art, in the past electromagnetic devices such as inductors or choke coils were usually formed by winding a conductor or wire, such as an insulated copper wire, around a cylindrical core. into, and generally this electromagnetic device is designed as a surface mount device (SMD) structure suitable for surface mount technology.

In recent years, with the development of electronic components towards smaller size and higher performance, the demand for coil devices with smaller size and higher performance is increasing. In addition, the efficiency of the above-mentioned coil device can be measured from its saturation current (saturation current, I _sat ) and DC resistance (DC resistance, DCR). However, with the current structure of the coil device, it is very difficult to further reduce its size and volume.

Therefore, there is still a need for an improved electromagnetic device in the art, which can further reduce its volume and size in addition to better performance, such as higher saturation current, lower DC resistance and better efficiency. .

Contents of the invention

The main purpose of the present invention is to provide an improved electromagnetic device, which has a smaller volume and can be manufactured by means of electroplating stacking technology or lamination stacking technology to obtain high yield.

In order to achieve the above object, an embodiment of the present invention provides an electromagnetic device, which includes a coil unit with a multi-layer stacked structure; a molded body covering the coil unit; and two electrodes electrically coupled respectively to both ends of the coil unit. The line width of each layer of the multi-layer stacked structure may be between 180-240 microns, and the thickness may be between 40-60 microns. Wherein the coil unit can be manufactured by electroplating lamination process or pressing technology.

An embodiment of the present invention provides a method for manufacturing an electromagnetic device. First, a coil unit is formed, which has a multi-layer wire pattern; a molded body is formed to cover the coil unit, wherein the molded body includes a magnetic material; then, two electrodes are formed, respectively electrically coupled to the coil unit two ends.

According to an embodiment of the present invention, the above-mentioned method for forming a coil unit includes: first providing a substrate, and then forming a first patterned photoresist layer on the substrate, and the first patterned photoresist layer includes an opening , then fill the opening with electroplated copper to form a first conductor pattern, and then remove the first patterned photoresist layer; cover a dielectric layer on the first conductor pattern, the dielectric The layer has a via hole, and then a copper layer is electroplated on the dielectric layer, so that the copper layer fills the via hole, and then a second patterned photoresist layer is formed on the copper layer, Then etching away the copper layer not covered by the second patterned photoresist layer, thus forming a second conductive pattern stacked on the first conductive pattern, wherein the first conductive pattern and the first conductive pattern The two wire patterns together constitute the winding of the coil unit.

According to another embodiment of the present invention, the above-mentioned method for forming a coil unit includes: firstly providing a substrate with a first circuit pattern thereon; laminating and pressing the substrate with a laminated film, the laminated film comprising An insulating layer and a copper foil layer; then at least one blind hole is formed in the laminated film; and an electroplated copper layer is formed on the laminated film to fill the blind hole to form a via plug, electrically connecting the first circuit pattern and the electroplated copper layer; and patterning the electroplated copper layer and the copper foil layer to form a second circuit pattern, wherein the first circuit pattern and the first circuit pattern The two circuit patterns jointly constitute the winding of the coil unit.

In order to make the above objects, features and advantages of the present invention more comprehensible, several preferred implementations are listed below and described in detail with accompanying drawings. However, the preferred embodiments and drawings described above are for reference and illustration only, and are not intended to limit the present invention.

Description of drawings

FIG. 1 is a schematic side perspective view of an electromagnetic device according to an embodiment of the present invention.

FIG. 2 is an exploded schematic diagram of a coil unit of the electromagnetic device in FIG. 1 .

3 to 12 are schematic diagrams illustrating a method for fabricating an electromagnetic device in cross-section according to an embodiment of the present invention.

Figures 13 to 14 illustrate an electromagnetic device according to another embodiment of the present invention, wherein Figures 13A and 13B are side perspective views of the coil unit of the electromagnetic device at different angles, and Figures 14A to 14D are layers of the coil unit Schematic diagram of the wiring layout.

15 to 23 are cross-sectional schematic diagrams illustrating a method for fabricating an electromagnetic device according to another embodiment of the present invention.

24 and 25 illustrate different aspects of the package of the electromagnetic device in the embodiment of the present invention.

Wherein, the reference signs are explained as follows:

1 Electromagnetic Devices

1a Electromagnetic devices

1b Electromagnetic Devices

10 Coil unit

12,12a,12b shaped body

13 Electrodes

100 coil stack structure

101-106 Coil pattern

101a-106a slot gap

120 Conductive column

201-205 Interlayer plug

3 Electromagnetic Devices

300 Substrate

300a Perforation

301 insulation core layer

302 copper layer

303 Via plug

310 patterned photoresist layer

310a opening

320 First wire pattern

330,430,480 Dielectric layer

330a, 430a Dielectric hole

330b opening

340,440 Copper layer

340a, 440a Via plug

350,450 Patterned photoresist layer

360,460 Second wire pattern

412 Molded body

412a Central Magnetic Column

5 Electromagnetic Devices

500 Coil unit

500a Central perforation

501-504 Coil pattern

510 Coil unit

512 Molded body

512a Central Magnetic Column

521,525 side extension

521a, 525a side

522-524 Inner layer

522a, 523a, 524a via plug

531-534, 541-544 Ends

550,552,554 via plug

561-564 Slit gap

6a,6b Unpackaged electromagnetic devices

600 Substrate

601 insulation core

602,603 Copper foil layer

604,605 Electroplated copper layer

612,614 perforations

612a, 614a Via plug

620,630 Laminated die

622,632 Insulation layer

623,633 Copper foil layer

642,644,652,654 blind holes

642a,644a652a,654a Via plug

662,663 Electroplated copper layer

702-705 Line Pattern

722-725 Line Pattern

730 Insulation protection layer

Detailed ways

The details of the present invention will be described below with reference to the accompanying drawings, and the content in these drawings constitutes a part of the detailed description of the specification and is shown in the form of specific examples of practicable embodiments. The following examples are described in sufficient detail to enable those skilled in the art to implement. Of course, other embodiments may be implemented, and any structural, logical, or electrical changes may be made without departing from the embodiments described herein. Therefore, the following detailed description should not be taken as limiting, but rather, the embodiments contained therein will be defined by the appended claims.

Please refer to FIGS. 1 and 2 , wherein FIG. 1 is a schematic side perspective view of an electromagnetic device according to an embodiment of the present invention, and FIG. 2 is an exploded schematic view of a coil unit of the electromagnetic device in FIG. 1 . As shown in Figures 1 and 2, an electromagnetic device 1, such as a choke coil or an inductor, includes a single-winding (single-winding) coil unit 10, which is encapsulated by a molded body 12, wherein the molded body 12 can be such as cuboid, cube or other shapes, and there is no certain limitation. In addition, the electromagnetic device 1 further includes two electrodes 13 electrically coupled to corresponding two terminals of the coil unit 10 . The electrodes 13 can protrude from opposite sides of the molded body 12 to facilitate electrical connection with other circuit devices. According to an embodiment of the present invention, the molded body 12 may be a magnetic material composed of resin and magnetic powder, and is formed around the coil unit 10 through press molding. In addition, the magnetic powder includes iron powder, ferrite powder, ferrous alloy powder or any suitable magnetic material.

According to an embodiment of the present invention, the above two electrodes 13 may be formed together with corresponding layers of the coil unit 10 to form an integral structure. However, those skilled in the art should understand that the above two electrodes 13 may be part of the lead frame. The above-mentioned two electrodes 13 can be concavely folded along opposite side surfaces of the molded body 12, which is convenient for the subsequent surface mount process.

According to the embodiment of the present invention, the coil unit 10 is manufactured by electroplating lamination technology or lamination stacking technology, and the details of the process will be described later. According to the embodiment of the present invention, the coil unit 10 is a single-turn, single-winding, multi-layer structure, such as a six-layer metal stack structure as shown in FIG. 2 . The coil patterns of each layer of the coil unit 10, such as the labels 101-106 in the second figure, can have a line width of about 180-240 microns, for example, the line widths of the coil patterns 101-106 of each layer can be 210 microns, and about A thickness of 40-60 microns, such as 46 microns. There is an insulating layer (not shown in the figure) between each layer of coil patterns 101-106 to insulate each layer of coil patterns 101-106 from each other. To simplify the illustration, the insulating layers formed between the coil patterns 101 - 106 of the coil unit 10 are omitted in FIGS. 1 and 2 . According to an embodiment of the present invention, the thickness of the insulating layer may be between 2-10 microns, such as 5 microns. In addition, the number of layers of the coil unit 10 can be between 2-8. However, those skilled in the art should understand that the number of layers of the above-mentioned coil unit 10 can be adjusted according to design requirements, and the present invention is not limited thereto.

According to the embodiment of the present invention, when viewed from above, the coil patterns 101-106 of each layer of the coil unit 10 can be circular or oval strip patterns, and they are non-closed circular patterns, in other words, as shown in the reference numerals 101a-106a in FIG. 2 As shown, there is a slit gap between the two ends of each layer of coil patterns 101-106. According to the embodiment of the present invention, the slits 101a-106a of the coil unit 10 are not aligned in the thickness direction, but the slits of adjacent two layers have an offset, for example, 150 in the clockwise direction. ~180 microns of offset, so that the back end of the upper layer, such as the coil pattern 101, can be electrically connected to the front end of the next layer, such as the coil pattern 102, via via plugs (represented by reference numerals 201-205). The series configuration of the turns on this single coil unit. The aforementioned via plugs 201 - 205 respectively pass through the thickness of each insulating layer, are located between the coil patterns 101 - 106 , and may have a diameter of about 180 microns.

3 to 12 are schematic cross-sectional views of a method for manufacturing an electromagnetic device according to an embodiment of the present invention. As shown in FIG. 3 , firstly, a substrate 300 such as a copper clad laminate (CCL) is provided. The substrate 300 may have at least one copper layer 302 stacked on an insulating core layer 301 , such as a dielectric layer or glass epoxy, and at least one via plug 303 passing through the entire thickness of the substrate 300 . The aforementioned via plug 303 may be a plated through hole, which may be fabricated by mechanical perforation or laser perforation combined with an electroplating process. To simplify the description, the figures only illustrate the layer structures formed on one side of the substrate 300, however, those skilled in the art should understand that the same stacked structure can be formed on the other side of the substrate 300, and use the disclosed The same steps as in the examples are carried out.

Then a patterned photoresist layer 310 is formed on the surface of the substrate 300 . The patterned photoresist layer 310 includes an opening 310a exposing a portion of the copper layer 302 . For example, each opening 310a has a width of about 210 microns and a depth of about 50 microns.

As shown in FIG. 4 , an electroplating process is then performed to fill the opening 310 a with copper metal, thus forming a first conductive pattern 320 with a line width of 210 microns and a thickness of about 46 microns. Then, the patterned photoresist layer 310 is removed. The shape of the first conducting pattern 320 is as shown in layers 101-106 in FIG. 1 and FIG. 2 . It is also worth noting that the above-mentioned first conductive pattern 320 may have a vertical sidewall profile, but is not limited thereto.

As shown in FIG. 5 , after the first wire patterns 320 are formed, the copper layer 302 between the first wire patterns 320 is then removed. Next, a dielectric layer 330 is conformally covered on the surface of the first conductive pattern 320 . A via hole 330 a is formed in the dielectric layer 330 , exposing part of the top surface of each first conductive pattern 320 , wherein the dashed line indicates that the via hole 330 a is in a different section from the cross-sectional structure in the current figure. Openings 330 b may be formed in the dielectric layer 330 between the first wire patterns 320 .

As shown in FIG. 6 , another electroplating process can be performed to completely form a copper layer 340 on the substrate 300 . A copper seed layer (not shown in the figure) may be formed by sputtering before forming the copper layer 340 . The copper layer 340 can be filled into the via hole 330a to form a via plug 340a. In addition, the aforementioned copper layer 340 may fill the opening 330b. Then a patterned photoresist layer 350 is formed on the copper layer 340 to define the second layer pattern of the coil unit of the electromagnetic device.

As shown in FIG. 7 , the copper layer 340 not covered by the patterned photoresist layer 350 is etched away, for example, by wet etching, so that a second wire pattern 360 is stacked on the first wire pattern 320 . The above-mentioned second conductive pattern 360 is shaped like the layers 101-106 in FIG. 1 and FIG. 2, and is electrically connected to the lower first conductive pattern 320 through the via layer plug 340a. The above-mentioned second conductive pattern 360 may have an inclined sidewall profile, but is not limited thereto.

As shown in FIGS. 8 to 10, repeat the steps in FIGS. The holes 330a are in different cross-sections (as shown in FIG. 2, the upper and lower positions of the interposer plug are staggered). Then, the copper layer 440 is fully electroplated on the substrate 300, a via plug 440a is formed in the via hole 430a, a patterned photoresist layer 450 is formed on the copper layer 440 (FIG. 9), and a third wire pattern 460 is formed. (Figure 10). Similarly, the shape of the above-mentioned third conductive pattern 460 is the layers 101 - 106 in FIG. 1 and FIG. 2 , and is electrically connected to the lower second conductive pattern 360 through the via plug 440 a. In addition, the above-mentioned third conductive pattern 460 may have an inclined sidewall profile, but is not limited thereto.

As shown in FIG. 11 , the dielectric layer 480 is conformally covered on the third wire pattern 460 , so that the coil stack structure 100 on one side of the substrate 300 is formed. As mentioned above, the same coil stack structure can be formed on the other side of the substrate 300 by using the same steps above.

As shown in FIG. 12 , part of the substrate 300 is finally removed by means of laser or mechanical drilling, and a through hole 300a is formed in the center of the coil stack structure 100 , and then the magnetic material composed of resin and magnetic powder is pressed and packaged. A molded body 412 is formed around the coil stack structure 100 . The molded body 412 fills the through hole 300a to form a central magnetic column 412a, so that the coil stack structure 100 surrounds the central magnetic column 412a, thus completing an electromagnetic device 3 . It should be noted that the electromagnetic device 3 in the figure only shows the coil stack structure 100 on one side of the substrate 300 , of course, the electromagnetic device 3 may also include a coil stack structure on the other side of the substrate 300 , which is also sealed and covered by the molded body 412 .

Please refer to FIG. 13 to FIG. 14, which depict an electromagnetic device according to another embodiment of the present invention, wherein FIG. 13A and FIG. 13B are side perspective views of the coil unit of the electromagnetic device at different angles, and FIG. Schematic diagram of the circuit layout of each layer of the device. As shown in FIGS. 13 to 14 , the coil unit 510 of the electromagnetic device 5 also has a multi-layer coil structure, and is stacked on a substrate 500 layer by layer. In this example, the coils of each layer of the coil unit 510 are non-closed circular coil patterns, and the via layer plugs 550, 552, 554 that are staggered above and below each other are connected to each other, and there may be a dielectric layer between the coils of each layer. or insulating layer (not shown). The multi-layer coil structure can use laser or machine drill to form a central through hole 500a, and then use resin and magnetic powder to form a molded body 512 through pressure molding, and form a central magnetic column 512a in the central through hole 500a (Fig. 14).

As shown in FIG. 14A , one end of the coil pattern 501 of the first layer ( M1 ) includes a side extension 521 connected to an end 541 . There is a slit gap 561 between the end portion 541 and the end portion 531 , and the via layer plug 550 is located close to the end portion 531 for connecting the first-layer coil pattern 501 to the second-layer coil pattern 502 . The side extension 521 has an exposed side 521 a not covered by the molded body 512 and can be coupled with an external electrode.

As shown in FIG. 14B , the second layer ( M2 ) coil pattern 502 also has two ends 532 , 542 and a slit notch 562 , wherein the slit notch 561 and the slit notch 562 are staggered up and down. The via layer plug 552 is located close to the end portion 542 for connecting the second layer coil pattern 502 to the third layer coil pattern 503 .

As shown in FIG. 14C , the coil pattern 503 of the third layer ( M3 ) also has two ends 533 , 543 and a slit notch 563 , wherein the slit notch 563 and the slit notch 562 are staggered. The via layer plug 554 is located close to the end portion 543 for connecting the third layer coil pattern 503 to the fourth layer coil pattern 504 .

As shown in FIG. 14D, one end of the fourth layer (M4) coil pattern 504 includes a side extension 525, and there is a slit gap 564 between one end 534 and the end 544, and the position of the via layer plug 554 is set. Near the end portion 534 is used to connect the fourth layer coil pattern 504 to the third layer coil pattern 503 . The side extension 525 has an exposed side 525 a not covered by the molded body 512 and can be coupled with an external electrode. In addition, the side extension section 521 can be stacked to be coplanar with the side extension section 525 through the interconnect layers 522 , 523 , 524 and the via plugs 522 a , 523 a , 524 a. Certainly, the electromagnetic device of the present invention may have more than four layers, and may also have more layers.

15 to 23 are schematic cross-sectional views of a method for manufacturing an electromagnetic device according to another embodiment of the present invention. First, as shown in FIG. 15 , a substrate 600 is provided, including an insulating core 601 with copper foil layers 602 , 603 on opposite sides thereof. Then a drilling process, such as mechanical drilling, is performed to form through holes 612 and 614 in the substrate 600 .

As shown in FIG. 16, hole filling electroplating is then performed to form electroplated copper layers 604, 605 on the copper foil layers 602, 603, and make the electroplated copper layers 604, 605 fill the through holes 612, 614 to form interlayer plugs 612a, 614a.

As shown in FIG. 17 , circuit pattern etching is performed next, and the electroplated copper layers 604 , 605 and the copper foil layers 602 , 603 are respectively etched into circuit patterns 702 , 703 and circuit patterns 722 , 723 . Wherein, the circuit patterns 702 and 722 can be similar to the second layer coil pattern 502 and the interconnection layer 522 in FIG. 14B , and the circuit patterns 703 and 723 can be similar to the third layer coil pattern 503 and the interconnection layer 523 in FIG. 14C . The via plugs 612a, 614a are similar to the via plugs 552, 523a in FIG. 14C.

As shown in Figure 18, the laminated films 620 and 630 are resin-coated copper foils, wherein the laminated film 620 includes an insulating layer 622 and a copper foil layer 623, and the laminated film 630 includes an insulating layer 632 and a copper foil layer 633. The layers 620 and 630 are laminated and pressed together with the substrate 600 .

As shown in FIG. 19 , laser ablation may be used to form blind holes 642 and 644 in the laminated film 620 , and form blind holes 652 and 654 in the laminated film 630 . The blind holes 642 and 652 reveal part of the circuit patterns 702 and 703 respectively, and the blind holes 644 and 654 respectively reveal parts of the circuit patterns 722 and 723 .

As shown in FIG. 20 , a desmear process and a copper electroplating process are performed to form electroplated copper layers 662 and 663 . Electroplated copper layers 662 and 663 respectively fill the blind holes 642 , 644 and blind holes 652 , 654 to form via plugs 642 a , 644 a and via plugs 652 a , 654 a.

As shown in FIG. 21 , circuit pattern etching is performed again, and the electroplated copper layers 662 and 663 and the copper foil layers 623 and 633 are respectively etched into circuit patterns 704 and 705 and circuit patterns 724 and 725 . Wherein, the circuit patterns 704 and 724 can be similar to the first layer coil pattern 501 and the side extension 521 in FIG. 14A , and the circuit patterns 705 and 725 can be similar to the fourth layer coil pattern 504 and the interconnection layer 524 in FIG. 14D . Vias 642a, 644a are similar to vias 550, 522a in FIG. 14A. Vias 652a, 654a are similar to vias 554, 524a in FIG. 14D.

Next, as shown in Figure 22A and Figure 23A, parts of the insulating layers 622, 632 and the insulating core 601 can be removed by means of mechanical drilling or micro-etching, and then sprayed with an insulating protective layer 730, thus completing a separate unpackaged electromagnetic device 6a. Alternatively, as shown in FIG. 22B and FIG. 23B , first screen print the insulating protective layer 730, and then remove part of the insulating protective layer 730, insulating layers 622, 632 and insulating core 601 by mechanical drilling or micro-etching, etc. Encapsulated electromagnetic device 6b. Follow-up can continue to be packaged with resin and magnetic powder pressure molding.

24 and 25 illustrate different aspects of the package of the electromagnetic device in the embodiment of the present invention.

As shown in FIG. 24 , the electromagnetic device 1 a includes a single-wound coil unit 10 as shown in FIG. 1 , and is molded with a molded body 12 to form a rectangular parallelepiped, a cube or other three-dimensional structures. There are also two electrodes 13 , which are respectively electrically coupled to corresponding two ends of the coil unit 10 . The above two electrodes 13 are completely covered in the molded body 12 . The molded body 12 may be formed around the coil unit 10 by press-molding a magnetic material including resin and magnetic powder. The magnetic powder may comprise iron powder, ferrite powder, ferrous alloy powder or any suitable magnetic material. In addition, two conductive elements or conductive pillars 120 are embedded in the molded body 12, which are electrically connected to the electrodes 13, so that the coil unit 10 can be connected with a circuit board or an external module (not shown in the figure).

As shown in FIG. 25 , the electromagnetic device 1 b includes a single-wound coil unit 10 as shown in FIG. 1 , which is partially covered by a molded body 12 a and a molded body 12 b. Another two electrodes 13 are respectively electrically coupled to corresponding two ends of the coil unit 10 . The above two electrodes 13 are partially exposed outside the molded body 12, so that the coil unit 10 can be connected with a circuit board or an external module (not shown in the figure).

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (16)

1. an electromagnetic device is characterized in that, comprises:

One coil unit has a multiple-level stack structure;

One formed body coats described coil unit; And

Two electrodes are electrically coupled to respectively two end points of described coil unit.

2. electromagnetic device according to claim 1 is characterized in that, described multiple-level stack structure comprises an insulated substrate and the lattice coil pattern is positioned on the described insulated substrate.

3. electromagnetic device according to claim 1 is characterized in that, described multiple-level stack structure has a central perforation, and described formed body is filled described central hole.

4. electromagnetic device according to claim 1 is characterized in that, described formed body comprises resin and Magnaglo.

5. electromagnetic device according to claim 1 is characterized in that, each of described coil unit layer is annular or avette strip pattern.

6. electromagnetic device according to claim 5 is characterized in that, has a slit breach between two ends of described each layer.

7. electromagnetic device according to claim 6 is characterized in that, the slit breach of one deck of described multiple-level stack structure and the slit breach of adjacent bed have a side-play amount at thickness direction.

8. electromagnetic device according to claim 1 is characterized in that, the rear end on a upper strata of described multiple-level stack structure is electrically connected to the front end of a lower floor via an interlayer connector, is formed in series winding configuration of each circle on the described coil unit.

9. electromagnetic device according to claim 1 is characterized in that, has insulating barrier between each layer of described multiple-level stack structure.

10. a method of making electromagnetic device is characterized in that, comprises:

Form a coil unit, have the multi-layer conductor leads pattern;

Form a formed body, coat described coil unit, wherein said formed body comprises a magnetic material; And

Form two electrodes, be electrically coupled to respectively the two-end-point of described coil unit.

11. the method for making electromagnetic device according to claim 10 is characterized in that, the step of described formation one coil unit comprises:

One substrate is provided;

Form one first patterning photoresist layer on described substrate, described the first patterning photoresist layer comprises an opening;

Described opening is inserted in electro-coppering, formed one first wire pattern;

Remove described the first patterning photoresist layer;

One dielectric layer is covered on described the first wire pattern, and described dielectric layer has an interlayer hole;

On described dielectric layer, electroplate a bronze medal layer, make described copper layer fill up described interlayer hole;

On described copper layer, form one second patterning photoresist layer; And

The described copper layer that ablation is not covered by described the second patterning photoresist layer so forms one second wire pattern and is stacked on described the first wire pattern, the common coiling that consists of described coil unit of wherein said the first wire pattern and described the second wire pattern.

12. the method for making electromagnetic device according to claim 11 is characterized in that, described ablation is not the wet etching etching method by the method for the described copper layer of described the second patterning photoresist layer covering.

13. the method for making electromagnetic device according to claim 11 is characterized in that, described substrate is a copper clad laminate.

14. the method for making electromagnetic device according to claim 11 is characterized in that, described the second patterning photoresist layer is removed after forming described the second wire pattern.

15. the method for making electromagnetic device according to claim 10 is characterized in that, the step of described formation one coil unit comprises:

One substrate is provided, has one first wire pattern on it;

Make described substrate and the stacked and pressing of a laminated film, described laminated film comprises an insulating barrier and a copper foil layer;

In described laminated film, form at least one blind hole;

On described laminated film, form a copper electroplating layer and make it fill up described blind hole, form an interlayer connector and be electrically connected described the first line pattern and described copper electroplating layer; And

The described copper electroplating layer of patterning and described copper foil layer form one second wire pattern, the common coiling that consists of described coil unit of wherein said the first wire pattern and described the second wire pattern.

16. the method for making electromagnetic device according to claim 15 is characterized in that, after finishing described the second wire pattern, other includes:

Get rid of described insulating barrier and the described substrate of part; And

Form an insulating protective layer.

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