Abstract
A magnetic member having a substantially annular structure includes a non-magnetic matrix and magnetic particles embedded in the matrix. The magnetic member may be arranged on or in a component carrier.
Claims
1. A magnetic member having a substantially annular structure, the magnetic member comprising: a non-magnetic matrix; and magnetic particles embedded in the matrix.
2. The magnetic member according to claim 1, comprising at least one of the following features: wherein the matrix is electrically insulating; wherein the matrix is diamagnetic; wherein the relative magnetic permeability μ.sub.r of the matrix is in a range from 0.999 to 1.001; wherein the matrix comprises or consists of at least one of the group consisting of a temperature stable polymer, a resin, in particular an epoxy resin, and polyimide; wherein the matrix is solid and/or liquid; wherein the magnetic particles are at least one of the group consisting of ferromagnetic, ferrimagnetic, permanent magnetic, soft magnetic, a ferrite, a metal oxide, and an iron alloy, in particular alloyed silicon; wherein the relative magnetic permeability μ.sub.r of the magnetic particles is in a range from 2 to 1,000,000; wherein the magnetic particles are magnetically stable at least up to 200° C., in particular at least up to 260° C.; wherein at least part of the magnetic particles is, in particular at least 50% of the magnetic particles are, spaced with respect to each other without direct physical contact with other magnetic particles, and with material of the matrix in between adjacent ones of said spaced magnetic particles; wherein at least part of the magnetic particles comprises a magnetic core and an electrically insulating shell covering the magnetic core; wherein substantially an entire exterior surface of the substantially annular structure is constituted by electrically insulating material; configured for generating a circumferentially closed magnetic field substantially in an interior of the magnetic member; wherein the substantially annular structure is free of air gaps; wherein the substantially annular structure has at least one air gap, in particular a plurality of circumferentially distributed air gaps.
3. The magnetic member according to claim 1, further comprising: an electrically conductive coil structure at least partially surrounding the substantially annular structure.
4. A component carrier, comprising: a stack comprising at least one electrically conductive layer structure and/or at least one electrically insulating layer structure; and a magnetic member comprising magnetic particles embedded in a non-magnetic matrix assembled to the stack.
5. The component carrier according to claim 4, wherein the magnetic member is surface mounted on the stack.
6. The component carrier according to claim 4, wherein the magnetic member is embedded in the stack.
7. The component carrier according to claim 4, further comprising: an electrically conductive coil structure at least partially surrounding the magnetic member and being arranged at least partially within the stack.
8. The component carrier according to claim 7, wherein the at least one electrically conductive layer structure forms at least part of the electrically conductive coil structure.
9. The component carrier according to claim 7, wherein the electrically conductive coil structure comprises a plurality of vertical segments and a plurality of horizontal segments connected to form a plurality of windings.
10. The component carrier according to claim 9, comprising at least one of the following features: wherein the vertical segments comprise plated through-holes and/or slots filled with electrically conductive material; wherein the horizontal segments are located in two parallel planes between which the vertical segments are connected; wherein the horizontal segments extend radially outwardly with respect to a common center; wherein the horizontal segments are substantially triangular.
11. The component carrier according to claim 4, wherein the component carrier is configured as one of the group consisting of an inductor, a wireless charger, a transformer, a DC/DC converter, an AC/DC inverter, a DC/AC inverter, and an AC/AC converter.
12. The component carrier according to claim 4, comprising at least one of the following features: a plurality of magnetic members comprising magnetic particles embedded in a non-magnetic matrix assembled to the stack, each magnetic member being embedded in a respective one of multiple stacked cores of the stack; wherein at least one of the electrically conductive layer structures comprises at least one of the group consisting of copper, aluminum, nickel, silver, gold, palladium, and tungsten, any of the mentioned materials being optionally coated with supra-conductive material such as graphene; wherein the at least one electrically insulating layer structure comprises at least one of the group consisting of resin, in particular reinforced or non-reinforced resin, for instance epoxy resin or bismaleimide-triazine resin, FR-4, FR-5, cyanate ester resin, polyphenylene derivate, glass, prepreg material, polyimide, polyamide, liquid crystal polymer, epoxy-based build-up film, polytetrafluoroethylene, a ceramic, and a metal oxide; wherein the component carrier is shaped as a plate; wherein the component carrier is configured as one of the group consisting of a printed circuit board, a substrate, and an interposer; wherein the component carrier is configured as a laminate-type component carrier.
13. A method of manufacturing a magnetic member, comprising: embedding magnetic particles in a non-magnetic matrix; and shaping the magnetic member so as to form a substantially annular structure.
14. A method, comprising: providing a component carrier with at least one magnetic member, the magnetic member comprising a non-magnetic matrix with magnetic particles embedded in the matrix; and adjusting magnetic properties of the component carrier.
15. The method according to claim 14, wherein adjusting comprises changing an amount of the magnetic particles and/or an amount of the matrix, a size of the magnetic particles, and/or a mutual distance between the magnetic particles in the matrix.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0066] FIG. 1, FIG. 2 and FIG. 3 illustrate different views of magnetic members with magnetic particles in a non-magnetic matrix according to exemplary embodiments of the invention.
[0067] FIG. 4, FIG. 5 and FIG. 6 illustrate cross-sectional views of transformers produced using magnetic members and coil structures according to exemplary embodiments of the invention.
[0068] FIG. 7, FIG. 8, FIG. 9, FIG. 10, FIG. 11, FIG. 12, FIG. 13, FIG. 14, FIG. 15 and FIG. 16 illustrate cross-sectional views of structures obtained during manufacturing a component carrier, shown in FIG. 16, with an embedded magnetic member such as the one shown in FIG. 1 to FIG. 3 and an intrinsically formed coil structure according to an exemplary embodiment of the invention.
[0069] FIG. 17, FIG. 18 and FIG. 19 illustrate plan views of component carriers according to exemplary embodiments of the invention having a magnetic member such as the one shown in FIG. 1 to FIG. 3.
[0070] FIG. 20 and FIG. 21 illustrate three-dimensional views of component carriers having a magnetic member such as the one shown in FIG. 1 to FIG. 3 according to exemplary embodiments of the invention.
[0071] FIG. 22, FIG. 23 and FIG. 24 illustrate plan views of inductor structures having a magnetic member such as the one shown in FIG. 1 to FIG. 3 which may be implemented in component carriers according to exemplary embodiments of the invention.
[0072] FIG. 25, FIG. 26, FIG. 27, FIG. 28, FIG. 29 and FIG. 30 illustrate cross-sectional views of structures obtained during manufacturing a component carrier, as shown in FIG. 30, with an embedded magnetic member such as the one shown in FIG. 1 to FIG. 3 and an intrinsically formed coil structure according to another exemplary embodiment of the invention.
[0073] FIG. 31, FIG. 32, FIG. 33, FIG. 34, FIG. 35, FIG. 36, FIG. 37, FIG. 38 and FIG. 39 illustrate cross-sectional views of structures obtained during manufacturing a component carrier, shown in FIG. 39, with an embedded magnetic member such as the one shown in FIG. 1 to FIG. 3 and an intrinsically formed coil structure according to still another exemplary embodiment of the invention.
[0074] FIG. 40, FIG. 41, FIG. 42, FIG. 43, FIG. 44, FIG. 45, FIG. 46 and FIG. 47 illustrate cross-sectional views of structures obtained during manufacturing a component carrier, shown in FIG. 47, with an embedded magnetic member such as the one shown in FIG. 1 to FIG. 3 and an intrinsically formed coil structure according to yet another exemplary embodiment of the invention.
DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS
[0075] The illustrations in the drawings are schematically presented. In different drawings, similar or identical elements are provided with the same reference signs.
[0076] Before, referring to the drawings, exemplary embodiments will be described in further detail, some basic considerations will be summarized based on which exemplary embodiments of the invention have been developed.
[0077] According to an exemplary embodiment of the invention, component carrier applications (in particular PCB based applications) may be accomplished with embedded magnetic materials with intrinsic non-magnetic (in particular polymer-filled (microscopic) air gaps. In particular, an exemplary embodiment may use magnetic particles surrounded with a polymer matrix, which acts as an intrinsic air gap. Particle-type magnetic material with intrinsic air gaps formed by non-magnetic matrix material may make it possible to achieve magnetic properties which may be specifically in compliance with a certain application. Thus, the present inventors have surprisingly found that polymer composites with a plurality of magnetic particles therein may provide intrinsic air gap properties. This may also provide a wide range of design parameters for fine-tuning the magnetic properties of a corresponding magnetic member.
[0078] Advantageously, microscopic air gaps may be used to stabilize the behavior of the magnetic member over electric current. Said microscopic or distributed air gaps may additionally be much better in terms of magnetic field fringing (i.e., a phenomenon according to which a magnetic field is running out of the core) than macroscopic gaps in a ring-shaped magnetic member. Moreover, the flexibility of adjusting the magnetic properties of the magnetic member by the adjustment of one or more dedicated or macroscopic air gaps and/or by the adjustment of distributed or microscopic air gaps may significantly increase the flexibility of a component carrier designer. In particular for high current magnetic applications, an adjustment of the magnetic properties may be accomplished according to exemplary embodiments of the invention by correspondingly designing the dedicated and/or the distributed air gaps. For low current magnetic applications (for instance involving electric current below 1 Ampère), dedicated or macroscopic air gaps may also be completely omitted. According to an exemplary embodiment of the invention, a component carrier (in particular a PCB, printed circuit board) with embedded magnetic material having intrinsic polymer-filled air gaps is provided.
[0079] Advantageously, a non-conductive coating around each magnetic particle may increase the resistivity of the magnetic material and may improve the air gap properties as well as the electrical isolation against electrically conductive structures.
[0080] If a temperature stable polymer is used as a binder, i.e., as material for the matrix, reliability of the magnetic member and a component carrier implementing such a magnetic member may be improved.
[0081] In particular, exemplary embodiments can be used to create PCB-based magnetic components for the following applications: wireless charging (both transmitter and receiver) units, power transformers for isolated power supplies, power inductors for non-isolated power supplies, shielding layers, antenna configurations, signal transformers, common mode chokes, differential mode chokes, current sense transformers, RFID devices, and NFC devices. In particular, embedding magnetic materials in a non-magnetic matrix into a component carrier stack may allow the production of inductors and transformers for PCB-based power modules as well as sensors, wireless charging units and other applications.
[0082] Since material in a surrounding of the magnetic member (for instance electrically conductive layer structures of a component carrier stack in which the magnetic member is embedded) can be electrically conductive, it may be advantageous that the magnetic particles are electrically isolated from such electrically conductive structures (for instance from copper in a PCB). This may be accomplished by a dielectric matrix of the annular structure.
[0083] For designing embedded inductors and transformers in terms of component carrier technology, PCB production processes may employ the formation of coils around an embedded magnetic inlay in inner layers of a PCB stack. However, magnetic materials may go into saturation when used at higher magnetic field strength. This may render it advantageous to introduce one or more air gaps into the magnetic core. The present inventors have surprisingly found that the space between magnetic particles filled with non-magnetic matrix material (for instance a polymer) may act as an intrinsic air gap. Since usable magnetic materials may be electrically conductive to a certain extent, it may be advantageous to electrically insulate the magnetic material against electrically conductive structures in a surrounding of the magnetic member. For instance, this may be accomplished by dielectric matrix material, a coating of the magnetic particles with a dielectric shell, the lamination of electrically isolating layers on both sides of the annular structure of the magnetic member to isolate against the conductive layer structures, and/or the formation of conductive vias and through holes which may be isolated by via-in-via technology.
[0084] In particular, it may be possible to embed the described magnetic material as an inlay, but it may also be provided as continuous layer (which may for instance be embedded in a stack of a component carrier as a whole).
[0085] Depending on an application, surface-mounted magnetic components may be considered as the largest components inside power modules. By having magnetic material embedded in inner layers of a component carrier such as a PCB, it may be possible to make conductive structures around the magnetic material to create coils for different applications. Magnetic materials may go into saturation when used at higher magnetic field strength compared to those for which the magnetic materials are initially designed. Since an application may require high magnetic field strength, it may be advantageous to introduce one or more air gaps into the magnetic core to prevent the magnetic material from going into saturation, which may deteriorate or even reversibly destroy magnetic properties.
[0086] The present inventors have surprisingly found that the space between magnetic particles filled with polymer material may functionally act as an intrinsic air gap. If such materials are used, an additional air gap cut into the core shape may be dispensable for the device to function as intended. Different materials have been tested which has confirmed this conclusion.
[0087] Another conventional shortcoming which may be overcome by exemplary embodiments of the invention is the issue that some of the materials are electrically conductive to a certain extent (due to low resistivity of the magnetic material), so it may be advantageous that the magnetic layer is isolated against the conductive structures. This may be achieved by laminating insulating layers on both sides of the magnetic layer to isolate them against the conductive layer in the build-up. If continuous magnetic layers are used, conductive vias and through holes passing through the magnetic layer need to be isolated by via-in-via technology.
[0088] Magnetic material can be embedded as an inlay, as a continuous layer or in combination with other components. The height of the magnetic material can be adopted to the height of one or more optional other embedded components (including active components and/or passive components).
[0089] A gist of an exemplary embodiment of the invention is thus the use of magnetic materials based on magnetic particles surrounded by a non-magnetic (for instance polymer) matrix, which functionally acts as an intrinsic air-gap. Moreover, a further exemplary aspect is the introduction of isolation layers to realize a PCB build-up with an embedded magnetic inlay. Furthermore, another exemplary aspect is the use of embedding technology to realize target applications when prefabricated inlays are used. Highly advantageously, the described magnetic material with intrinsic air gaps may make it possible to achieve desired magnetic properties adjusted in accordance with the requirements of a specific application.
[0090] For instance, an embedding method (see FIG. 7 to FIG. 16) may be used to embed one or more pre-fabricated magnetic inlays (with non-magnetic matrix and magnetic particles embedded therein) into the inner layers of a PCB. Then, electrically conductive structures can be fabricated on top and bottom side as well as around these inlays by etching the conductive structures and making connections by vias or through holes between the conductive layers. The vias can be filled with copper or other conductive materials to realize connections between the layers, forming coils and/or other structures.
[0091] Different materials may be used for those magnetic members or inlays. In particular, magnetic particles in a resin-based matrix may be used. For instance, metal particles (such as flakes), ferrite particles, particles in resin-based pastes (in terms of a binder system), etc., may be used. Appropriate materials may be selected in accordance with a specific application. Materials with magnetic particles in a polymer matrix proved particularly advantageous for many applications due to their intrinsic air gap. Such intrinsic air gaps may make the characteristic of inductance versus current bias stable. An additional advantage is that eddy currents can be significantly reduced due to the small size of the magnetic particles. Additionally, each magnetic particle can be surrounded with an isolation barrier (such as a dielectric coating) made of electrically isolating materials (for instance of an organic or inorganic material).
[0092] In terms of a first method, introducing the magnetic material into a PCB may be accomplished by embedding a pre-shaped inlay in the area where the magnetic properties are required. Alternatively, introduction may be carried out in a second method by introducing a continuous layer into the PCB build-up. The first method allows making electrical connections in the areas where no magnetic material is present. The second method may involve isolation of the conductive vias against the magnetic material. This can be achieved by drilling holes, filling with resin and drilling a smaller hole into the resin filler, which is subsequently plated and filled with conductive material (for instance copper). Another method may be to coat the walls of the hole by any other method with isolation material.
[0093] For some magnetic materials, it may be advantageous to provide additional isolation layers before the conductive layers are made in the build-up. Introduction of those isolation layers may be advantageous due to the low resistivity of the magnetic material. In particular, the following solutions can be realized in this context: [0094] Lamination with a polymer-based resin sheet (polymer sheet without glass fiber reinforcement such as a bonding sheet), polymer sheet with glass fiber reinforcement (for instance prepreg), etc.; [0095] Liquid or paste coating applied by spraying, printing, etc.
[0096] FIG. 1 to FIG. 3 illustrate different views of magnetic members 108 with magnetic particles 162 in the non-magnetic matrix 160 according to exemplary embodiments of the invention.
[0097] Referring to FIG. 1, a side view of a magnetic member 108 is shown. Although not derivable from FIG. 1, the magnetic member 108 may be an annular or ring-like structure with a central through hole which is not visible in FIG. 1. The annular structure of magnetic member 108 of FIG. 1 comprises a non-magnetic matrix 160 and a large plurality of magnetic particles 162 (in particular at least 100, more particularly at least one thousand particles) embedded in the matrix 160.
[0098] The matrix 160 may be made of a solid electrically insulating and substantially non-magnetic material such as an epoxy resin or polyimide. The substantially non-magnetic property (i.e., having a relative magnetic permeability μ.sub.r very close to one) of the matrix 160 ensures that the matrix material effectively functions as a non-magnetic gap maintaining a spacing between the magnetic particles 162 having pronounced magnetic properties and thus high values of the relative magnetic permeability pr. The dielectric property of the matrix 160 does not only form an intrinsic non-magnetic gap in an interior of the substantially annular body, but also ensures advantageously that no undesired electrically conductive paths are formed when the magnetic member 108 is coupled with an electronic periphery, for instance is embedded in a component carrier 100, as shown for instance in FIG. 7 to FIG. 16 or FIG. 25 to FIG. 47.
[0099] For example, the magnetic particles 162 may be made of a ferrite or a metal oxide. Other materials, such as iron-based materials with silicon additive are possible as well. For instance, the relative magnetic permeability μ.sub.r of the magnetic particles 162 may be 1,000. Thus, the magnetic particles 162 have the capability of strongly enhancing an external magnetic field, which may for instance be generated by a powered coil structure 110, see FIG. 4. In view of these properties, magnetic member 108 according to FIG. 1 is highly appropriate for applications such as inductors, wireless charges, transformers, etc. Preferably, the magnetic particles 162 are magnetically stable at least up to 260° C. In other words, the magnetic particles 162 may be configured for withstanding temperatures which may occur for instance during lamination processes in terms of component carrier technology. In view of this property, the magnetic member 108 is highly suitable for being embedded in a laminate-type component carrier 100.
[0100] As shown in FIG. 1 as well, the magnetic particles 162 are spaced with respect to each other by material of the matrix 160 in between. As a result, the resin spacers in form of material of matrix 160 between adjacent magnetic particles 162 form permanent dielectric microscopic gaps having an impact on the magnetic performance of the magnetic member 108.
[0101] For instance, the annular structure of the magnetic member 108 may be free of macroscopic gaps, for example as in FIG. 22. In such an embodiment, the adjustment of the magnetic properties of the magnetic member 108 (in particular its magnetic saturation properties) can be accomplished by adjusting the relative amounts of material of matrix 160 and material of magnetic particles 162, as well as dimensions of the particles 160 and of the microscopic gaps. For instance, typical diameters of the magnetic particles 162 may be b=5 μm or B=15 μm. For example, a typical distance between neighboring magnetic particles 162 may be 1=5 μm.
[0102] Alternatively, the annular structure may have one or more macroscopic air gaps 114, for example as in FIG. 18. The adjustment of the magnetic properties of the magnetic member 108 and in particular of its saturation properties may then be made by adjusting the number and width d (see FIG. 17) of macroscopic air gaps 114 and/or by adjusting the properties of the microscopic gaps, as described in the preceding paragraph.
[0103] The geometric configurations with or without macroscopic gaps allow the formation or generation of a circumferentially closed magnetic field substantially in an interior of the magnetic member 108.
[0104] In particular, the magnetic member 108 may be used for adjusting magnetic properties of a component carrier 100 in which the magnetic member 108 is embedded. In such a context, the magnetic properties may be adjusted by adjusting an amount of material of the magnetic particles 162 and of the matrix 160, a size (b, B) of the magnetic particles 162, and/or a mutual distance (I) between the magnetic particles 162 in the matrix 160.
[0105] As shown in FIG. 1, substantially an entire exterior surface of the substantially annular structure is electrically insulating. In other words, the exterior surface of the illustrated magnetic member 108 is entirely dielectric, so that no artificial electrically conductive paths are formed between the magnetic member 108 and an environment.
[0106] Referring to FIG. 2, a side view of another magnetic member 108 is shown. The configuration of FIG. 2 may be correspondingly as described for FIG. 1. However, according to FIG. 2, each of the magnetic particles 162 comprises a magnetic core 164 and an electrically insulating shell 166 covering or coating the magnetic core 164. By taking this measure, it can be prevented that magnetic particles 162, when made of an electrically conductive material, form undesired electrically conductive paths in an electronic periphery (for instance when embedded in a stack 102 of a component carrier 100).
[0107] Referring to FIG. 3, a cross-sectional view of an annular magnetic member 108 with a central through hole 163 (which may for instance be filled with resin material or a platelet, such as the one described below referring to reference sign 118) according to another exemplary embodiment of the invention is shown. According to FIG. 3, the size of the particles 162 varies over a broader range. In other words, the magnetic particles 162 of FIG. 3 have a size distribution.
[0108] All magnetic members 108 described below referring to FIG. 4 to FIG. 47 may comprise a non-magnetic matrix 160 with magnetic particles 162 embedded therein, for instance as illustrated in FIG. 1 to FIG. 3.
[0109] FIG. 4 to FIG. 6 illustrate cross-sectional views of transformers produced using magnetic member 108 and coil structures 110 according to exemplary embodiments of the invention. The magnetic member 108 may be embedded in a stack 102 of a component carrier 100.
[0110] Referring to FIG. 4, the magnetic member 108 is shown alone, i.e., without stack 102. Referring to FIG. 5, the magnetic member 108 is shown embedded in a stack 102. Referring to FIG. 6, the illustrated magnetic member 108 is shown together with a surface mounted component 165.
[0111] FIG. 4 and FIG. 6 show that the annular structure composed of matrix 160 and magnetic particles 162 can be surrounded by electrically conductive structures of an electrically conductive coil structure 110. The coil structure 110 is composed by cooperating vertical segments 120 and horizontal segments 122, as described below in further detail.
[0112] FIG. 7 to FIG. 16 illustrate cross-sectional views of structures obtained during manufacturing a component carrier 100 with an embedded magnetic member 108 and an intrinsically formed coil structure 110, shown in FIG. 16, according to an exemplary embodiment of the invention.
[0113] FIG. 7 illustrates a cross-sectional view of a plate-shaped laminate-type layer stack 102, which may be a core. The laminated stack 102 is composed of electrically conductive layer structures 104 and an electrically insulating layer structure 106. For example, the electrically conductive layer structures 104 may comprise patterned copper foils (and optionally one or more vertical through connections, for example copper filled laser vias). The electrically insulating layer structure 106 may comprise a resin (such as epoxy resin), optionally comprising reinforcing particles therein (for instance, glass fibers or glass spheres). For instance, the electrically insulating layer structure 106 may be made of prepreg or FR4. The layer structures 104, 106 may be connected by lamination, i.e., the application of pressure and/or heat.
[0114] Thus, FIG. 7 illustrates the cross-section of a PCB (printed circuit board) core. The stack 102 is composed of a central electrically insulating layer structure 106 covered on both opposing main surfaces thereof with a respective patterned copper foil as electrically conductive layer structure 104.
[0115] Referring to FIG. 8, an opening 190 is formed in the stack 102. More specifically, opening 190 may be cut in the stack 102 shown in FIG. 1. The formed opening 190 is later used for accommodating a magnetic member 108 to be embedded in the stack 102. For instance, the opening 190 may be formed by laser cutting, mechanically cutting or etching.
[0116] Referring to FIG. 9, a sticky layer 130 may be attached to a bottom of the stack 102 for closing the opening 190. According to FIG. 9, the upper main surface of the sticky layer 130 is sticky or adhesive. As will be described below, the sticky layer 130 will function as a temporary carrier. For instance, the sticky layer 130 may be a sticky foil or a sticky plate. Since the opening 190 is closed at a bottom side by the sticky layer 130, a cavity is defined which has a volume corresponding to the opening 190 and is closed at the bottom side by the sticky layer 130. The exposed upper main surface of the temporary carrier shown in FIG. 9 is adhesive.
[0117] Referring to FIG. 10 a magnetic member 108 (such as the one shown in FIG. 1 to FIG. 3) is subsequently attached on the sticky layer 130 and in the cavity of the stack 102. Said magnetic member 108 may be circumferentially closed or may comprise a plurality of separate segments (see for instance FIG. 17 and FIG. 18) which can be assembled separately on the sticky layer 130. In order to obtain the structure shown in FIG. 10, the magnetic member 108 may be inserted into the opening 190 and may be adhered to the adhesive upper side of the sticky layer 130. This is particularly advantageous when the magnetic member 108 is composed of multiple separate bodies. Adhering the magnetic member 108 on the sticky side of the sticky layer 130 may define an exact position of the magnetic member 108 in the cavity. The magnetic member 108 or its separate bodies are thereby also prevented from sliding within the cavity. A dimension of gaps (see reference sign 114 in FIG. 17 and FIG. 18) between separate bodies of the magnetic member 108 may be used as a design parameter for precise controlling the characteristic of the component carrier 100 with embedded magnetic member 108. For instance, dimensioning of said gaps 114 may also fulfil the task of ensuring that the magnetic field in the annular magnetic member 108 does not go into saturation. Also, the geometric properties of the constituents of the magnetic member 108, i.e., of matrix 160 and magnetic particles 162, may be used as design parameters for adjusting the magnetic saturation properties, functioning as intrinsic or microscopic gaps. Thus, multiple ring segments or other separate bodies constituting together the magnetic member 108 may be advantageous. However, placing multiple separate bodies constituting together the magnetic member 108 into the opening 190 might be conventionally an issue because of the risk of a slight sliding or motion of one or more of the individual bodies of the magnetic member 108. This may introduce artefacts into the magnetic behavior of the magnetic member 108. However, by closing the bottom of the stack 102 comprising the opening 190 with the sticky layer 130 and by subsequently adhering the individual bodies of the magnetic member 108 on the sticky layer 130 during an assembly process, it may be ensured that the individual bodies of the magnetic member 108 are located at well-defined positions and are brought in a well-defined orientation with respect to each other. Otherwise, a subsequently described method of manufacturing a coil structure 110 surrounding the magnetic member 108 may damage or even destroy the magnetic member 108. For instance, this may happen when mechanically drilling for defining the position of vertical through-connections, and hereby an erroneous drilling may occur also into material of erroneously positioned and/or oriented bodies of the magnetic member 108.
[0118] Still referring to FIG. 10, a central opening 116 of the magnetic member 108 may be filled with a dielectric platelet 118, such as an FR4 platelet. This may ensure that only a small amount of adhesive material or of flowable resin material will be required during a lamination procedure described referring to FIG. 11 to fill the small spaces between the platelet 118 and the magnetic member 108. The undesired formation of voids in an interior of the stack 102 may thus be reliably prevented. Hence, the described procedure may ensure a complete filling of the opening 190 with the magnetic member 108, the platelet 118 and the laminated dielectric material. Assembling the platelet 118 in the cavity and on the sticky layer 130 may be performed before, during or after assembling the magnetic member 108 on the sticky layer 130.
[0119] Referring to FIG. 11, the magnetic member 108 is fixed in place in the opening 190 by laminating adhesive material 132 onto a top side of the structure shown in FIG. 10. Thus, after assembly of the magnetic member 108, a first lamination procedure may be carried out which is described referring to FIG. 11. During this lamination, a further electrically conductive layer structure 104 and/or a further electrically insulating layer structure 106 is attached to the upper main surface of the arrangement shown in FIG. 10 and is made subject to lamination. Preferably, the electrically insulating layer structure 106 attached to the upper side of the stack 102 may be made of an at least partially uncured dielectric such as a prepreg sheet. During the lamination process, heat and/or mechanical pressure is applied to the stack 102 to be connected. During this lamination, the material of the previously at least partially uncured dielectric material may become flowable or liquid and may flow into tiny gaps between the assembled magnetic member 108 and the sidewalls of the stack 102 as well as below the magnetic member 108 to fill also gaps here. During the lamination, said flowable material will cure and will be resolidified so that the magnetic member 108 is then fixed in place.
[0120] As an alternative to the described lamination, it is also possible to apply a liquid adhesive (for instance by dispensing or printing) into remaining empty spaces of the opening 190 and cure the liquid adhesive so that the magnetic member 108 is fixed in place.
[0121] Referring to FIG. 12, the sticky layer 130 may be optionally (for instance depending on the particular sticky material applied) removed after completing the lamination. After the described lamination procedure, the temporary carrier, sticky film or positioning layer may thus be removed from the bottom side of the component carrier 100 to be manufactured. Since, as a result of the lamination procedure, the magnetic member 108 with its individual ring segments has been fixed in place at the correct position within the opening 190, the sticky layer 130 is no longer needed for providing support and defining assembly positions. It is thus removed to obtain a structure shown in FIG. 12.
[0122] As shown in FIG. 13, the obtained structure may then be made subject to a second lamination procedure. This time, a further electrically conductive layer structure 104 and a further electrically insulating layer structure 106 may be laminated to the lower main surface of the structure of FIG. 12. In the shown embodiment, the second lamination procedure is carried out so as to obtain a symmetric arrangement of the layer stack 102 in the vertical direction (if the sticky material remains connected to the stack 102, the arrangement of layers may be slightly asymmetric). As a result, further adhesive material 133 covers a bottom of the magnetic member 108.
[0123] The dielectric material added according to FIG. 12 and/or FIG. 13 can also include additives increasing the thermal conductivity and thereby forming a heat removal structure 177 for removing heat from the later formed coil structure 110 and/or the magnetic member 108. In other words, the magnetic component in form of the magnetic member 108 can be embedded in a resin based on a thermo-prepreg (which may have a heat conductivity in a range from 2 W/mK to 8 W/mK).
[0124] Referring to FIG. 14, the electrically conductive layer structures 104 are then trimmed so as to form an electrically conductive coil structure 110 surrounding the magnetic member 108. In order to obtain the structure shown in FIG. 14, vertical drilling holes may be formed extending through the entire stack 102. Subsequently, said drilling holes, which may be formed by mechanically drilling, may be filled partially or entirely with electrically conductive material (such as copper) by plating. Thus, the obtained vertical through-connections may be hollow cylindrical or circular cylindrical structures of copper. The copper filled vertical through-holes may form vertical segments 120 of coil structure 110 being formed to surround the annular magnetic member 108 with a plurality of coil windings.
[0125] In order to obtain the structure shown in FIG. 15, the previously continuous metal foils (for instance copper foils) on the upper and lower main surface of the illustrated structure can be patterned so as to form horizontal segments 122 to complete the formation of closed loops or windings running circumferentially around the annular magnetic member 108. As a result, a plurality of closed windings is formed by the interconnection of the vertical segments 120 provided by the plated through-holes and the horizontal segments 122 provided by the patterned metal foils. The magnetic member 108 has a central opening (see reference sign 116 in FIG. 10) through which part of the coil structure 110 extends. Another part of the coil structure 110 is arranged laterally exteriorly of the magnetic member 108. The coil structure 110 extends over a larger vertical range than the magnetic member 108. More specifically, the coil structure 110 protrudes vertically beyond the magnetic member 108 upwardly and downwardly.
[0126] Referring to FIG. 16, component carrier 100 according to an exemplary embodiment of the invention is obtained by further laminations both on the top side and the bottom side of the structure shown in FIG. 15. In order to obtain the component carrier 100 shown in FIG. 16, a further build-up may be carried out, i.e., one or more additional electrically conductive layer structures 104 and/or one or more additional electrically insulating layer structures 106 may be added on top and/or on bottom of the structure shown in FIG. 15 by a further lamination procedure.
[0127] A heat removal structure 177 may be provided as part of the stack 102. It may be configured for removing heat from the coil structure 110 and/or the magnetic member 108. The heat removal structure 177 may comprises a metallic material and a thermally conductive prepreg (which may have a heat conductivity in a range from 2 W/mK to 20 W/mK, in particular in a range from 2 W/mK to 8 W/mK). Both of the laminated structures can be made out of a thermo-prepreg. In addition to that, a copper member can be mounted on the surface of the thermo-prepreg.
[0128] The illustrated laminate-type plate-shaped component carrier 100 may be embodied as a printed circuit board (PCB). The component carrier 100 comprises the stack 102 composed of the electrically conductive layer structures 104 and the electrically insulating layer structures 106. The magnetic member 108 is embedded in the stack 102. Part of the electrically conductive layer structures 104 form the integrally formed electrically conductive coil structure 110 surrounding the magnetic member 108. For instance, the magnetic member 108 may be made of a non-magnetic matrix 160 with magnetic particles 162 embedded therein. The magnetic member 108 may be embodied as a closed ring or as an open ring having a central opening 116 filled with the dielectric platelet 118, which may be preferably made of FR4. The dielectric platelet 118 forms part of the component carrier 100. Said coil structure 110 is composed of the vertical segments 120 and the horizontal segments 122 which are interconnected to form a plurality of windings. The vertical segments 120 may be formed as plated through-holes or slots filled with electrically conductive material. The horizontal segments 122 may lie in two parallel planes and may for instance comprise substantially triangular sub-sections being interconnected with the vertical segments 122 thereby forming coil windings surrounding the magnetic member 108. Still referring to FIG. 16, a minimum distance D between the electrically conductive coil structure 110 and the magnetic member 108 may be advantageously larger than 10 μm and less than 30 μm.
[0129] FIG. 17 to FIG. 19 illustrate plan views of component carriers 100 according to exemplary embodiments of the invention.
[0130] Referring to FIG. 17, the magnetic member 108 is a ring structure composed of three ring segments 112 with three gaps 114 in between. A thickness d of different gaps 114 between ring segments 112 of the magnetic member 108 vary preferably less than 20%. Even more preferably, the multiple gaps 114 between adjacent ring segments 112 of the magnetic member 108 may have substantially the same length d.
[0131] The plan view of the magnetic member 108 with surrounding integrated coil structure 110 of FIG. 17 shows that in this embodiment the magnetic member 108 is provided as a substantially annular body composed of three ring segments 112 with three gaps 114 in between. The coil structure 110 surrounding the magnetic member 108 comprises the substantially triangular circle sector type horizontal segments 122. Cylindrical vertical segments 120 are provided at a radially inner side of the horizontal segments 122 and at a radially outer side of the horizontal segments 122 and can thereby connect with the horizontal segments 122 to form windings of the coil structure with substantially rectangular geometry in a side view (compare FIG. 16). Coil connections are denoted with reference numeral 150 in FIG. 17.
[0132] Now referring to FIG. 18, a plan view of a magnetic member 108 surrounded by windings of the coil structure 110 of an exemplary embodiment of the invention is shown. As indicated with reference numeral 152, the vertical segments 120 with circular shape can be substituted and/or supplemented by slots filled with electrically conductive material such as copper and extending vertically to the paper plane of FIG. 18. Descriptively speaking, it is for instance possible to combine multiple (in particular two or three) radially arranged and/or tangentially arranged circular vertical segments 120 to a single common vertical slot segment 152. This may provide a low ohmic configuration which increases the current carrying capability, reduces the generation of heat in an interior of the component carrier 100 and results in lower losses.
[0133] By providing a zigzag connection of horizontal segments 122 and vertical segments 120, closed windings of the coil structure may be created.
[0134] As can be derived from FIG. 17 and FIG. 18, a trajectory connecting centers of windings of the coil structure 110 is a circumferentially closed loop extending within a horizontal plane. Central axes of the windings of the coil structure 110 extend within a horizontal plane. This is indicated schematically in FIG. 17 with a circle 153.
[0135] FIG. 19 shows the magnetic member 108 with coil structure 110 together with further constituents of a component carrier 100 according to an exemplary embodiment of the invention.
[0136] FIG. 20 and FIG. 21 illustrate three-dimensional views of component carriers 100 according to exemplary embodiments of the invention.
[0137] FIG. 20 shows a three-dimensional view of a component carrier 100 according to an exemplary embodiment of the invention with a number of components 159 which can be coupled to the described magnetic structure.
[0138] FIG. 21 shows a component carrier 100 configured as a wireless charger. What concerns the wireless charging function of the component carrier 100, applying an electric current to the coil structure 110 generates an electromagnetic field in the environment of the component carrier 100. The magnetic member 108 of very high magnetic permeability enhances the electromagnetic field. When a mobile phone or other electronic device to be charged in a wireless manner is positioned in an environment of the component carrier 100 and when such an electronic device comprises a corresponding receiver unit, the electromagnetic field generated by the component carrier 100 may be used for charging the electronic device.
[0139] FIG. 22 to FIG. 24 illustrate plan views of inductor structures which may be implemented in component carriers 100 according to exemplary embodiments of the invention.
[0140] In the embodiment of FIG. 22, the magnetic member 108 with surrounding coil structure 110 is embodied as a toroid structure. This has the advantage of a very low leakage flux.
[0141] As shown in the embodiment of FIG. 23, an equal configuration is illustrated which is highly appropriate for coupled inductors. Moreover, such a configuration ensures a sufficiently large via spacing and a low leakage flux.
[0142] In the embodiment of FIG. 24, the magnetic member 108 has a core configuration with high via spacing and sufficient leakage flux.
[0143] FIG. 25 to FIG. 30 illustrate cross-sectional views of structures obtained during manufacturing a component carrier 100, shown in FIG. 30, with an embedded magnetic member 108 such as the one shown in FIG. 1 to FIG. 3 and an intrinsically formed coil structure 110 according to another exemplary embodiment of the invention.
[0144] Referring to FIG. 25, an adhesive structure 181 (such as an adhesive paste) may be applied in different ways, for instance may be printed, on an electrically conductive layer structure 104, in particular a copper foil.
[0145] Referring to FIG. 26, a magnetic member 108 may be assembled and adhered to the adhesive structure 181 on said electrically conductive layer structure 104.
[0146] Referring to FIG. 27, the magnetic member 108 may be covered with electrically insulating layer structures 106 and a further electrically conductive layer structure 104. The electrically insulating layer structures 106 at lower levels may be provided with a through hole or a blind hole for accommodating the magnetic member 108 in said holes. More specifically, the magnetic member 108 may be laminated with cut-out prepreg layers. If at least one of said electrically insulating layer structures 106 is at least partially uncured (for instance is in a B-stage), no adhesive paste is needed in addition, since the constituents of the structure shown in FIG. 27 may be connected with each other by lamination, i.e., the application of heat and/or pressure.
[0147] Referring to FIG. 28, constituents of an electrically conductive coil structure 110 may be formed, for instance by drilling and plating.
[0148] Referring to FIG. 29, a structure is shown which is obtained by patterning electrically conductive layer structures 104 on both opposing main surfaces of the structure shown in FIG. 28.
[0149] Referring to FIG. 30, additional electrically conductive layer structures 104 and electrically insulating layer structures 106 are added on both opposing main surfaces of the structure shown in FIG. 29, to thereby complete manufacture of component carrier 100.
[0150] FIG. 31 to FIG. 39 illustrate cross-sectional views of structures obtained during manufacturing a component carrier 100 with an embedded magnetic member 108 (which may be configured as described referring to FIG. 1 to FIG. 3) and an intrinsically formed coil structure 110, shown in FIG. 39, according to another exemplary embodiment of the invention.
[0151] Referring to FIG. 31, a stack 102 composed of a central electrically insulating layer structure 106 and patterned electrically conductive layer structures 104 on both opposing main surfaces thereof is shown. For instance, stack 102 may be embodied as PCB (printed circuit board) core.
[0152] Referring to FIG. 32, a release layer 183 is formed at a surface of the stack 102. For instance, the release layer 183 may be printed in form of a waxy compound on the upper main surface of the stack 102 shown in FIG. 91. Thus, the release layer 183 may be made of a material being poorly adhesive with respect to other materials of stack 102.
[0153] Referring to FIG. 33, further electrically conductive layer structures 104 and electrically insulating layer structures 106 may be connected to both the upper main surface and the lower main surface of the structure shown in FIG. 32 to thereby embed the release layer 183 within the stack 102.
[0154] Referring to FIG. 34, previously continuous electrically conductive layer structures 104 on both opposing main surfaces of the structure illustrated in FIG. 33 are patterned.
[0155] Referring to FIG. 35, a circumferential cutting trench 187 is cut in the stack 102 to extend vertically up to the release layer 183. Cutting trench 187 may for example be formed by laser cutting or by mechanically cutting. Thereby, a stack piece 185 is separated from a rest of the stack 102. Laterally, piece 185 is separated by the cutting trench 187. At a bottom side, piece 185 is separated by the non-adhesive release layer 183.
[0156] Referring to FIG. 36, a blind hole-type opening 190 is formed in the stack 102 by removing said cap-shaped piece 185 from the stack 102. As shown, piece 185 is delimited at a bottom side by the release layer 183 and laterally by the circumferential or annular trench 187. Thereafter, the release layer 183 may be removed, for instance by stripping.
[0157] Referring to FIG. 37, an adhesive structure 181 is formed at a bottom surface of the blind hole-type opening 190. For instance, a layer of an adhesive material may be printed with a stencil. However, adhesive material can also be applied differently than printing, in particular either to the bottom surface of the cavity or to the downward-facing surface of the magnetic member 108 to be attached to or assembled in the cavity.
[0158] Referring to FIG. 38, a magnetic member 108 is mounted on the bottom surface in the opening 190 with the adhesive structure 181 in between. In other words, the magnetic member 108 may be assembled and accommodated in the opening 190.
[0159] Referring to FIG. 39, one or more further electrically conductive layer structures 104 and electrically insulating layer structures 106 may be laminated on top of the structure shown in FIG. 38 to thereby embed the magnetic member 108 within an interior of the stack 102.
[0160] Although not shown in detail, it is subsequently possible to create electrically conductive structures by drill and via technology, thereby forming electrically conductive coil structure 110. Reference is made to the description of FIG. 14 to FIG. 16.
[0161] FIG. 40 to FIG. 47 illustrate cross-sectional views of structures obtained during manufacturing a component carrier 100 (shown in FIG. 47) with an embedded magnetic member 108 (for instance having properties as described above referring to FIG. 1 to FIG. 3) and an intrinsically formed coil structure 110 according to another exemplary embodiment of the invention.
[0162] Referring to FIG. 40, a starting point of the manufacturing process may be a PCB-core as stack 102, which may be constituted for instance in a similar way as shown in FIG. 1 or FIG. 31.
[0163] Referring to FIG. 41, a blind hole-type opening 190 is formed with a closed bottom side in the stack 102 by depth routing.
[0164] Referring to FIG. 42, an adhesive structure 181 is formed on a bottom surface delimiting opening 190. For instance, said adhesive material may be applied by stencil printing.
[0165] Referring to FIG. 43, a magnetic member 108 is assembled on the bottom surface with the adhesive structure 181 in between. In other words, the magnetic member 108 is accommodated on a bottom surface of the routed stack 102 in the opening 190.
[0166] Referring to FIG. 44, one or more further electrically conductive layer structures 104 and electrically insulating layer structures 106 may be laminated on top and on bottom of the structure shown in FIG. 43 to thereby embed the magnetic member 108 in an interior of the stack 102.
[0167] Referring to FIG. 45, a portion of electrically conductive coil structure 110 is formed by a drill and fill process.
[0168] Referring to FIG. 46, the obtained structure is patterned.
[0169] Referring to FIG. 47, one or more further electrically conductive layer structures 104 and electrically insulating layer structures 106 may be laminated on top and on bottom of the structure shown in FIG. 46, to thereby complete manufacture of component carrier 100.
[0170] It should be noted that the term “comprising” does not exclude other elements or steps and the article “a” or “an” does not exclude a plurality. Also, elements described in association with different embodiments may be combined.
[0171] Implementation of the invention is not limited to the preferred embodiments shown in the figures and described above. Instead, a multiplicity of variants is possible which variants use the solutions shown and the principle according to the invention even in the case of fundamentally different embodiments.
