MAGNETIC CIRCUIT BOARD AND METHOD FOR MANUFACTURING SAME

Abstract

A circuit board (01), including at least two electrically conductive layers (02) arranged one above the other and at least one dielectric layer (03), which is arranged between adjacent electrically conductive layers (02), is provided. The circuit board (01) is characterized in particular in that the plate has at least two magnetically conductive layers (05), wherein each magnetically conductive layer (05) is arranged at least indirectly adjacent to an electrically conductive layer (02), and that the circuit board also has vertical recesses for accommodating magnetic vias (08) for connecting the magnetically conductive layers (05) in a specific manner. A method for producing such a circuit board (01) is provided.

Claims

1-10. (canceled)

11. A circuit board comprising: at least two electrically conductive layers situated one above the other and spaced apart from one another; at least one dielectric layer situated between the electrically conductive layers; at least two magnetically conductive layers spaced apart from one another, each magnetically conductive layer being situated at least indirectly adjacent to an electrically conductive layer, and vertical recesses for accommodating magnetic vias for magnetically connecting the magnetically conductive layers in a targeted manner.

12. The circuit board as recited in claim 11 wherein the magnetic vias include a magnetically conductive material introduced into the vertical recesses.

13. The circuit board as recited in claim 11 wherein the magnetically conductive layers include outer layers.

14. The circuit board as recited in claim 11 wherein a symmetrical sequence of the electrically conductive layers and the magnetically conductive layers is present.

15. The circuit board as recited in claim 14 wherein the symmetrical sequence includes insulating layers of the at least one dielectric layer.

16. The circuit board as recited in claim 11 wherein the magnetically conductive layers are made of ferromagnetic powder-filled plastic sheets or metal sheets.

17. The circuit board as recited in claim 11 wherein the magnetically conductive layers have magnetic flux-collecting properties or shielding properties.

18. The circuit board as recited in claim 11 wherein the circuit board is designed as a flexible circuit board.

19. The circuit board as recited in claim 11 wherein the electrically conductive layers form at least one coil.

20. The circuit board as recited in claim 11 wherein the circuit board is designed as a panel including a plurality of adjacently situated individual circuit boards, the magnetically conductive layers being applied over the entire surface area of the panel.

21. A method for manufacturing a multilayer circuit board, comprising the following steps: providing a multilayer circuit board including at least two electrically conductive layers spaced apart from one another, at least one dielectric layer situated between adjacent electrically conductive layers of the at least two electrically conductive layers, and at least two magnetically conductive layers situated in each case at least indirectly adjacent to one of the electrically conductive layers; introducing first and second recesses into the multilayer circuit board; introducing magnetically conductive material into the first recesses to establish magnetic connections between the magnetically conductive layers; metal-plating walls of the second recesses to establish electrical connections between the electrically conductive layers.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Preferred specific embodiments of the present invention are explained in greater detail below with reference to the appended figures. [0025] FIG. 1 shows a circuit board according to the present invention in a first specific embodiment; and [0026] FIG. 2 shows the circuit board according to the present invention in a second specific embodiment.

DETAILED DESCRIPTION

[0027] FIG. 1 shows a first specific embodiment of a circuit board 01 according to the present invention. Circuit board 01 in this case includes three electrically conductive layers 02 situated one above the other and spaced apart from one another. Copper is generally used as material for the electrically conductive layers in circuit boards. A dielectric layer 03 is situated in each case between two electrically conductive layers 02. The two outer electrically conductive layers 02 are each adjoined by an auxiliary layer 04, which is used for electrical, magnetic, and thermal insulation, and at the same time, for the mechanical connection. Auxiliary layers 04 are followed in each case by a magnetically conductive layer 05. In the specific embodiment shown, the two magnetically conductive layers 05 form the outer layers, i.e., the cover layer and the base layer of circuit board 01. Individual electrically conductive layers 02 and magnetically conductive layers 05 are mechanically connected to one another with the aid of dielectric layers 03 and auxiliary layers 04, which preferably takes place by adhesive bonding.

[0028] Electrically conductive layers 02 are designed as structured layers for forming a conductor structure. They are electrically connected to one another via electrical vias 07. Recesses whose walls are preferably metal-plated are introduced into circuit board 01 in order to create electrical vias 07. Alternatively, rivets, pins, or sleeves made of an electrically conductive material may be introduced into the recesses and mechanically connected to circuit board 01. The shape and size of electrical vias 07 vary, depending on the intended purpose. Smaller electrical vias may be drilled, for example, while larger vias are preferably milled. The electrical vias may be designed in such a way that they connect structures of all electrically conductive layers 02 to one another. Alternatively, electrical vias 07 may also extend only up to one electrically conductive layer 02 situated in the circuit board interior. It is also possible for electrical vias 07 to extend between electrically conductive layers 02 in the circuit board interior. Electrically conductive layers 02 preferably form at least one coil.

[0029] Magnetically conductive layers 05 are preferably designed as ferromagnetic powder-filled plastic sheets or metal sheets. For example, iron powder or ferrite powder of various alloys may be used as ferromagnetic powder. Magnetically conductive layers 05 are connected to one another with the aid of magnetic vias 08. The magnetic flux conduction is thus expanded into the third dimension in a targeted manner. Magnetic vias 08 are created by introducing recesses into circuit board 01. The recesses may likewise be drilled or milled. Depending on the application, these recesses penetrate all or only some of the layers of the circuit board. Magnetically conductive material is introduced into the recesses. The magnetically conductive material may be a paste which contains ferromagnetic powder such as iron powder or ferrite powder of various alloys. Alternatively, however, rivets, pins, or sleeves made of magnetically conductive material which are introduced into the recesses and mechanically connected to circuit board 01 may also be used.

[0030] Circuit board 01 shown in FIG. 1 has a symmetrical sequence of the various layers, which is advantageous in particular with regard to the thermal stability. However, embodiments are also possible which do not use a symmetrical sequence of the various layers.

[0031] For manufacturing circuit board 01 shown in FIG. 1, the circuit board may be manufactured, based on a conventional multilayer electrical circuit board, in a first step in which a magnetically conductive layer 05 is additionally attached as a cover layer and base layer, using the customary technologies and materials. Magnetically conductive layer 05 may be laminated on, for example. Magnetic vias 08 are created in the next step by introducing recesses into circuit board 01 by milling or drilling, and are subsequently filled with magnetically conductive material.

[0032] FIG. 2 shows a second specific embodiment of circuit board 01 according to the present invention. Circuit board 01 includes four electrically conductive layers 02, in each case two electrically conductive layers 02 indirectly situated one above the other being connected to one another via electrical vias 07. A dielectric layer 03 is situated in each case between two adjacent electrically conductive layers 02. A significant difference from the embodiment shown in FIG. 1 is that circuit board 01 includes magnetically conductive layers 05 in the circuit board interior. Magnetically conductive layers 05 are situated indirectly adjacent to electrically conductive layers 02 via auxiliary layers 04. In each case two magnetically conductive layers 05 are magnetically connected to one another in a targeted manner with the aid of magnetic vias 08.

[0033] The manufacture of the specific embodiment shown in FIG. 2 may take place in such a way that two subpackets, each made up of two electrically conductive layers 02, are initially created and mechanically connected with the aid of a dielectric layer 03. Recesses, whose walls are metal-plated to form electrical vias 07, are subsequently introduced into the two subpackets. Each subpacket is subsequently provided in each case with two magnetically conductive layers 05 with the aid of auxiliary layers 04. Magnetically conductive layers 05 now form the outer layers of the two subpackets. Appropriate recesses are subsequently introduced into the subpackets and filled with magnetically conductive material to implement magnetic vias 08. The subpackets are subsequently mechanically connected to one another with the aid of an auxiliary layer 04.

[0034] Circuit board 01 shown in FIG. 2 includes an additional auxiliary layer 04 in each case as the cover layer and the base layer, which is also used in particular to protect the circuit board from environmental influences.

[0035] Alternatively, circuit board 01 may also be manufactured by initially connecting all layers of circuit board 01 to one another. In this case, however, magnetic vias 08 must be created first, and only then are electrical vias 07 created.

LIST OF REFERENCE NUMERALS

[0036] 01 circuit board [0037] 02 electrically conductive layer [0038] 03 dielectric layer [0039] 04 auxiliary layer [0040] 05 magnetically conductive layer [0041] 06 [0042] 07 electrical vias [0043] 08 magnetic vias