Component Carrier With a Magnetic Element and a Manufacturing Method

Abstract

A component carrier includes a stack including at least one electrically conductive layer structure and/or at least one electrically insulating layer structure, a magnetic element assembled to the stack, and a dielectric layer structure on the stack. The magnetic element includes an embedded inductive element. The dielectric layer structure at least partially surrounds the magnetic element. Further, a manufacturing method and a use of photo-imaging are described.

Claims

1. A component carrier, comprising: a stack comprising at least one electrically conductive layer structure and/or at least one electrically insulating layer structure; a magnetic element assembled to the stack, wherein the magnetic element comprises an embedded inductive element; and a dielectric layer structure on the stack, wherein the dielectric layer structure at least partially surrounds the magnetic element.

2. The component carrier according to claim 1, wherein the magnetic element comprises: a magnetic matrix, and an electrically conductive structure that is at least partially embedded in the magnetic matrix to provide the inductive element.

3. The component carrier according to claim 2, wherein the electrically conductive structure is formed as a winding, in particular a coil-like structure, and wherein the directions of main extension of the winding are essentially parallel to the directions of main direction of the component carrier.

4. The component carrier according to claim 1, wherein the dielectric layer structure comprises a shift pattern that reflects a manufacturing step of laminating a second dielectric layer structure on a first dielectric layer structure to form the dielectric layer structure.

5. The component carrier according to claim 4, wherein the shift pattern comprises at least one of the group which consists of an alignment shift, a smearing, a tapering of a dielectric layer structure sidewall being in contact with a sidewall of the magnetic element.

6. The component carrier according to claim 4, wherein the shift pattern is established along a plane being essentially flush to an upper main surface of the electrically conductive structure and parallel to the directions of main extension of the component carrier.

7. The component carrier according to claim 1, wherein the dielectric layer structure comprises a cavity, and wherein the magnetic element is at least partially embedded in the cavity.

8. The component carrier according to claim 1, wherein the dielectric layer structure is a photo-imageable dielectric.

9. The component carrier according to claim 1, comprising at least one of the following features: wherein a lower main surface of the magnetic element is flush with an upper main surface of the stack; wherein an upper main surface of the magnetic element is flush with an upper main surface of the dielectric layer structure; wherein the component carrier further comprises: a further layer structure and/or a further stack arranged on the dielectric layer structure and/or on the magnetic element.

10. The component carrier according to claim 2, wherein the magnetic matrix comprises at least one of the following features: wherein the magnetic matrix continuously fills a volume around the electrically conductive structure and between windings of the electrically conductive structure; wherein the magnetic matrix comprises at least one of the group consisting of a rigid solid, and a paste; wherein the magnetic matrix comprises one of the group which consists of: electrically conductive, electrically insulating, partially electrically conductive and partially electrically insulating; wherein the relative magnetic permeability μ.sub.r of the magnetic matrix is in a range from 2 to 10.sup.6, in particular 10 to 1000, more in particular 20 to 80; wherein the magnetic matrix comprises at least one material of the group consisting of a ferromagnetic material, a ferrimagnetic material, a permanent magnetic material, a soft magnetic material, a ferrite, a metal oxide, a dielectric matrix, in particular a prepreg, with magnetic particles therein, and an alloy, in particular an iron alloy or alloyed silicon.

11. A method of manufacturing a component carrier, the method comprising: providing a stack comprising at least one electrically conductive layer structure and/or at least one electrically insulating layer structure; arranging a first dielectric layer structure on the stack; forming a first cavity within the first dielectric layer structure; placing a first magnetic element at least partially into the first cavity so that the first dielectric layer structure at least partially surrounds the first magnetic element; arranging a second dielectric layer structure on the first dielectric layer structure and the first magnetic element; forming a second cavity within the second dielectric layer structure; and placing a second magnetic element at least partially into the second cavity, so that the second dielectric layer structure at least partially surrounds the second magnetic element.

12. The method according to claim 11, wherein placing the first magnetic element further comprises: providing a plurality of gaps within the first magnetic element; and arranging an electrically conductive structure at least partially in the gaps, in particular in form of windings, so that an inductive element is provided, in particular wherein arranging the electrically conductive structure further comprises: providing a seed-layer to cover a respective bottom of the plurality of gaps; and at least partially filling the gaps by electro-plating, in particular with copper.

13. The method according to claim 11, wherein placing the second magnetic element further comprises: arranging the second magnetic element on, in particular directly on, the first magnetic element in order to embed the electrically conductive structure within magnetic material.

14. The method according to claim 11, wherein the first magnetic element comprises a first magnetic matrix, wherein the second magnetic element comprises a second magnetic matrix, and wherein the first magnetic matrix and the second magnetic matrix comprise a similar material or a different material.

15. The method according to claim 11, wherein forming the second cavity further comprises: exposing an upper main surface of the first magnetic element.

16. The method according to claim 11, wherein arranging the first dielectric layer structure and/or the second dielectric layer structure comprises lamination using at least one of heat and pressure.

17. The method according to claim 11, wherein the dielectric layer is a photo-imageable dielectric and wherein forming the first cavity and/or the second cavity comprises: exposing a part of the first photo-imageable dielectric layer structure and/or the second photo-imageable dielectric layer structure to photolithography.

18. The method according to claim 11, wherein forming the first cavity and/or the second cavity comprises: removing a part of the first dielectric layer structure and/or the second dielectric layer structure by etching or pre-cutting.

19. The method according to claim 11, wherein placing the first magnetic element and/or the second magnetic element further comprises screen printing.

20. A method, comprising: using photolithography to provide cavities in a dielectric layer structure; and embedding an inductive element-comprising magnetic element in a component carrier.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0083] FIG. 1 shows a side view of a component carrier with an embedded magnetic element according to an exemplary embodiment of the disclosure.

[0084] FIG. 2 shows a side view of a semi-finished component carrier with an embedded magnetic element according to a further exemplary embodiment of the disclosure.

[0085] FIG. 3 shows a detailed view of a magnetic element that comprises an inductive element in a magnetic matrix according to an exemplary embodiment of the disclosure.

[0086] FIG. 4 shows an example of a conventional circuit board with surface-mounted magnetic material.

[0087] FIG. 5A, FIG. 5B, FIG. 5C, FIG. 5D, FIG. 5E, FIG. 5F, FIG. 5G to FIG. 5H illustrate a first part of a method of manufacturing the component carrier according to an exemplary embodiment of the disclosure.

[0088] FIG. 6A, FIG. 6B, FIG. 6C, FIG. 6D, FIG. 6E, FIG. 6F, FIG. 6G, FIG. 6H, FIG. 6I, FIG. 6J, FIG. 6K to FIG. 6L illustrate a second part of a method of manufacturing the component carrier according to an exemplary embodiment of the disclosure.

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS

[0089] The illustrations in the drawings are schematically presented. In different drawings, similar or identical elements are provided with the same reference signs.

[0090] 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 disclosure have been developed.

[0091] According to an exemplary embodiment, large cavities are formed inside a photo-imageable dielectric layer which can be filled with magnetic paste. The cavity can be round, rectangular or any other shape depending on the application needed. Further, the cavity can be created by photolithography which avoids the expensive process of laser cutting of the core or time-consuming mechanical drilling (e.g., several hundreds of thousands of drills on one panel). Alternatively, cavities can be formed by etching or pre-cutting, whereby costs may be saved.

[0092] According to an exemplary embodiment, by stacking several PID layers, a cavity with higher thickness can be created which allows: more magnetic material printed inside the cavity thus achieving higher inductance values, and mechanical drilling can be eliminated which enables cost saving.

[0093] FIG. 1 shows a side view of a component carrier 100 with an embedded magnetic element according to an exemplary embodiment of the disclosure. The component carrier 100 comprises a stack 110 (e.g., a copper-clad laminate or a multilayer stack) comprising electrically conductive layer structures 104 and an electrically insulating layer structure 102 (e.g., a core layer).

[0094] A magnetic element 150 is surface mounted (assembled) to the stack 110 and comprises an embedded inductive element 120. The lower main surface 152 of the magnetic element 150 is directly placed on the stack 110 and is thus flush with the upper main surface 111 of the stack 110. The magnetic element 150 comprises a magnetic matrix 155 (a magnetic paste) and an electrically conductive structure 120 that is fully embedded in the magnetic matrix 155. The electrically conductive structure 120 comprises windings and thereby serves as the embedded inductive element 120. The magnetic element 150 has a planar shape (wherein the extension in z-direction is lower than the extension in x- and y-direction), so that the windings are arranged in a horizontal direction of the component carrier 100.

[0095] The component carrier 100 further comprises a dielectric layer structure 130, for example a photo-imageable dielectric (PID) layer structure 130 on the stack 110. Base materials for a PID application can include: i) thermosetting material: epoxy, BCB, phenol, ii) thermoplastic material: PI, PBO, and can comprise a photo initiator (photo sensitive agent) to be able to be cured by photo UV light.

[0096] The magnetic element 150 is embedded in the PID layer structure 130, so that the PID layer structure 130 fully surrounds the sidewalls of the magnetic element 150. The upper main surface 151 of the magnetic element 150 is flush with the upper main surface 131 of the PID layer structure 130 and is thus exposed. A further layer structure and/or a further stack can be arranged on the PID layer structure 130 (not shown).

[0097] The PID layer structure 130 comprises a shift pattern 140 that reflects a manufacturing step of laminating a second PID layer structure 130b on a first PID layer structure 130a to form the PID layer structure 130 (see FIG. 6). Said shift pattern 140 is established along a plane P being flush to the upper main surface 121 of the electrically conductive structure 120 and being parallel to the directions of main extension x, y of the component carrier 100.

[0098] Hereby, the shift pattern 140 comprises for example an alignment shift.

[0099] FIG. 2 shows a side view of a semi-finished component carrier 105 with an embedded magnetic element 150 according to a further exemplary embodiment of the disclosure. The device 105 shown in FIG. 2 is very similar to the one described in FIG. 1 with the difference that the electrically conductive structure 120 is embedded in a first part of the magnetic matrix 155a, so that the sidewalls of the electrically conductive structure 120 are surrounded by the magnetic matrix 155a. However, an upper surface 121 of the electrically conductive structure 120 is still exposed. The first part of the magnetic matrix 155a is surrounded by a first part of the dielectric layer structure 130a. The semi-finished product 105 is obtained at the process step shown in FIG. 6G (see below).

[0100] FIG. 3 shows a detailed view of a magnetic element 150 that comprises an inductive element 120 embedded in a magnetic matrix 155 according to an exemplary embodiment of the disclosure. It can be seen that the inductive element 120 is formed by an electrically conductive structure 120 (e.g., copper) winding that is formed in a coil-like manner. A starting point and an end point of the winding 120 are respectively electrically connected to a terminal. When an electric current is provided to the winding 120, an inductance is provided which is in turn amplified by the magnetic matrix 150. Since the magnetic element 150 comprises a planar shape, the electrically conductive structure 120 is oriented horizontally with respect to the component carrier 100. By providing the magnetic matrix 155, a large amount of magnetic material (e.g., in comparison to prior art example in FIG. 4) can be applied. As a consequence, a high inductance value can be obtained.

[0101] FIGS. 5A to 5H illustrate a first part of a method of manufacturing the component carrier 100 according to an exemplary embodiment of the disclosure.

[0102] As illustrated in FIG. 5A a layer stack 101 is provided with a first dielectric layer structure 130a on top that is further covered by a film layer 160 (e.g., a PET film). The dielectric layer structure in this example comprises a photo-imageable dielectric (PID).

[0103] As shown in FIG. 5B, photolithography (shown by arrows) is applied, wherein a first portion of the first dielectric layer structure 130a is covered by a mask (or LDI) 161, while a second portion of the first dielectric layer structure 130a is exposed. Instead of a mask, laser direct imaging (LDI) can be applied to cure the sections that need to be cured/structured (since there may be a need to structure the dielectric layer structure 130.

[0104] As illustrated in FIG. 5C, the exposed portion has been removed in order to obtain a first cavity 135a. Further the film layer 160 has been removed.

[0105] In optional process steps shown in FIGS. 5D-5F, the first cavity 135a (i.e., the sidewalls of the cavity) are further enlarged by repeating the process described in FIGS. 5A-5C.

[0106] As shown in FIGS. 5G and 5H, after developing and curing of the dielectric material, a robust first cavity 135a is provided in the first dielectric layer structure 130a.

[0107] FIGS. 6A to 6L illustrate a second part of a method of manufacturing the component carrier 100 according to an exemplary embodiment of the disclosure. The second method can directly build up on the first method and start with the product obtained in FIG. 5H.

[0108] As shown in FIG. 6A, a first magnetic element 150a is provided in form of a magnetic paste that is filled (poured) into the first cavity 135a by screen printing 163. Such a cavity can be formed by photo-imaging (when the dielectric layer structure 130 is a PID layer structure), etching, or by pre-cutting. Thus, a first magnetic element 150a is placed into the first cavity 135a, so that the first dielectric layer structure 130a surrounds the first magnetic element 150a.

[0109] As shown in FIG. 6B, the stencil (for screen printing) 163 is removed and a first curing step is performed.

[0110] As illustrated in FIG. 6C, overlapping magnetic material of the first magnetic element 150a is removed by grinding. A second curing step is performed.

[0111] As shown in FIG. 6D, a plurality of gaps 156 are provided within the first magnetic element 150a (e.g., “laser trenching”).

[0112] As illustrated in FIG. 6E, a seed-layer 164 is provided (e.g., using electroless-plating and/or sputtering) to cover respective bottoms of the plurality of gaps 156 and the upper main surface of the first dielectric layer structure 130a.

[0113] As shown in FIG. 6F, the gaps 156 are filled by electro-plating 165, in particular with copper. The metal layer 165 on top of the upper main surface of the first part of the dielectric layer structure 130a is increased. Thereby, an electrically conductive structure 120 is formed in the gaps 156 in form of windings, so that an inductive element is provided.

[0114] As illustrated in FIG. 6G, said metal layer 165 is removed chemically or mechanically (planarization) and the semi-finished product 105 described in FIG. 2 is obtained.

[0115] As shown in FIG. 6H, a second dielectric layer structure 130b is arranged (laminated) on the first PID layer structure 130a and the first magnetic element 150a.

[0116] As illustrated in FIG. 6I, a second cavity 135b is formed within the second dielectric layer structure 130b as described for FIGS. 5A-C.

[0117] As depicted in FIG. 6J, after film layer removal, developing and curing the second dielectric layer structure 130b is performed. The second cavity 135b is now arranged on top of the first magnetic element 150a and the embedded electrically conductive structure 120, whereby an upper main surface 151a of the first magnetic element 150a is exposed.

[0118] As illustrated in FIG. 6K, a second magnetic element 150b is placed into the second cavity 135b (by screen printing), so that the second dielectric layer structure 130b surrounds the second magnetic element 150b. The second magnetic element 150b is placed directly on the first magnetic element 150a in order to embed the electrically conductive structure 120 within magnetic material.

[0119] As shown in FIG. 6L, after removing of the stencil 163 that covers the dielectric layer structure 130, the following steps are performed: first curing, grinding, second curing. Then, the component carrier 100 described for FIG. 1 is obtained.

[0120] It should be noted that the term “comprising” does not exclude other elements or steps and the use of articles “a” or “an” does not exclude a plurality. Also, elements described in association with different embodiments may be combined.

[0121] 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.

REFERENCE SIGNS

[0122] 100 Component carrier [0123] 102 Electrically insulating layer structure [0124] 104 Electrically conductive layer structure [0125] 105 Semi-finished component carrier [0126] 110 Layer stack [0127] 111 Upper main surface layer stack [0128] 120 Electrically conductive structure, inductive element [0129] 121 Upper main surface electrically conductive structure [0130] 130 Dielectric (PID) layer structure [0131] 130a First part of dielectric layer structure [0132] 130b Second part of dielectric layer structure [0133] 131 Upper main surface dielectric layer structure [0134] 135a First cavity [0135] 135b Second cavity [0136] 140 Shift pattern [0137] 150 Magnetic element [0138] 150a First (part of) magnetic element [0139] 150b Second (part of) magnetic element [0140] 151 Upper main surface magnetic element [0141] 152 Lower main surface magnetic element [0142] 155 Magnetic matrix [0143] 155a First magnetic matrix [0144] 155b Second magnetic matrix [0145] 156 Gap [0146] 160 Film layer [0147] 161 Photo-mask [0148] 163 Stencil (screen printing) [0149] 164 Seed layer [0150] 165 Further conductive material [0151] P Plane [0152] 400 Conventional circuit board