Electronic device with embedded electronic component

Abstract

An electronic device includes a component carrier with a component carrier body, an electrically conductive layer, and an adhesive structure. The electronic device further includes an electronic component which is arranged within the component carrier body. The adhesive structure is formed between a surface of the electronic component and the electrically conductive layer and covers only a part of the surface of the electronic component. A remaining part of the surface of the electronic component is covered with the component carrier body.

Claims

1. An electronic device, comprising: a component carrier comprising a component carrier body, a substantially continuous electrically conductive layer, and an adhesive structure; an electronic component which is arranged within the component carrier body; wherein the adhesive structure is formed between a surface of the electronic component and the substantially continuous electrically conductive layer; wherein the adhesive structure covers a first part of the surface of the electronic component; wherein a remaining second part of the surface of the electronic component is covered with the component carrier body; and wherein all of the edge sections of the surface of the electronic component are free from the adhesive structure.

2. The electronic device according to claim 1, wherein the adhesive structure is a layer with a substantially constant thickness.

3. The electronic device according to claim 2, wherein the substantially constant thickness is in a range between 3 m to 300 m.

4. The electronic device according to claim 1, wherein the adhesive structure comprises at least one via for electrically contacting the embedded electronic component with the electrically conductive layer.

5. The electronic device according to claim 4, wherein an aspect ratio of the thickness of the adhesive structure and a diameter of the at least one via is in a range between d=1.2h and d=1.6h where d is the diameter of the at least one via and h is the thickness of the adhesive structure.

6. The electronic device according to claim 1, wherein the adhesive structure comprises a plurality of adhesive sub-structures, wherein the adhesive sub-structures are spatially separated from each other.

7. The electronic device according to claim 6, wherein a space between the adhesive sub-structures is filled with electrically insulating material.

8. The electronic device according to claim 1, wherein the component carrier is configured as one of the group consisting of a printed circuit board, and a substrate.

9. The electronic device according to claim 1, wherein the electronic component is selected from a group consisting of an active electronic component, a passive electronic component, an electronic chip, a storage device, a filter, an integrated circuit, a signal processing component, a power management component, an optoelectronic interface element, a voltage converter, a cryptographic component, a transmitter and/or receiver, an electromechanical transducer, a sensor, an actuator, a microelectromechanical system, a microprocessor, a capacitor, a resistor, an inductance, a battery, a switch, a camera, an antenna, and a logic chip.

10. The electronic device according to claim 1, wherein the component carrier body comprises at least one electrically insulating structure which comprises at least one of the group consisting of resin, cyanate ester, glass, glass fibers, prepreg material, polyimide, liquid crystal polymer, epoxy-based Build-Up Film, FR4 material, a ceramic, and a metal oxide.

11. The electronic device according to claim 1, wherein the substantially continuous electrically conductive layer comprises at least one of the group consisting of copper, aluminum, and nickel.

12. The electronic device according to claim 1, wherein the component carrier is a laminate-type component carrier.

13. The electronic device according to claim 1, wherein the adhesive structure is electrically insulating.

14. The electronic device according to claim 1, wherein the said surface of the electronic component is equal to one main surface of the electronic component.

15. A method of manufacturing an electronic device, the method comprising: providing a component carrier comprising a component carrier body, a substantially continuous electrically conductive layer and an adhesive layer; applying the adhesive structure on the substantially continuous electrically conductive layer; equipping the component carrier with an electronic component by placing the electronic component on the adhesive structure, such that the adhesive structure covers a first part of the surface of the electronic component and such that all of the edge sections of the surface of the electronic component are free from the adhesive structure; embedding the electronic component within the component carrier body by laminating an electrically insulating structure of the component carrier body onto the electronic component, such that a remaining second part of the surface of the electronic component is covered with the electrically insulating structure of the component carrier body.

16. The method according to claim 15, wherein applying the adhesive structure comprises applying a plurality of adhesive sub-structures spatially separated from each other.

17. The method according to claim 15, wherein embedding the electronic component further comprises filling a space between the adhesive sub-structures with electrically insulating material of the electrically insulating structure of the component carrier body.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The aspects defined above and further aspects of the invention are apparent from the examples of embodiment to be described hereinafter and are explained with reference to these examples of embodiment.

(2) FIG. 1 shows a cross-sectional view of a conventional electronic device.

(3) FIG. 2 shows a cross-sectional view of an electronic device according to an exemplary embodiment of the invention.

(4) FIG. 3 shows a cross-sectional view of an electronic device with a conventional thick adhesive layer.

(5) FIG. 4a shows a cross-sectional view of an intermediate product of the electronic device according to another embodiment of the invention.

(6) FIG. 4b shows the finished electronic device according to the exemplary embodiment.

(7) FIG. 5 shows a plan view of the adhesive sub-structures of the embodiment of FIGS. 4a and 4b.

(8) FIG. 6 shows arrangements of the adhesive structure according to an exemplary embodiment.

(9) FIG. 7 shows a classification table for the Moisture Sensitivity Level Test.

(10) FIG. 8 shows different types of microvias.

(11) FIG. 9 shows a bar diagram representing the void formation reported for each of the microvia designs of FIG. 8.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

(12) FIG. 2 shows an electronic device 200 according to an exemplary embodiment. The electronic device 200 comprises an electrically conductive layer 220, an electronic component 250 and an adhesive structure 230 which adheres the electronic component 250 to the electrically conductive layer 220. The electronic device 200 further comprises a component carrier body 210. The shown component carrier body 210 comprises further layers 210-1, 210-2, 210-3, which may be prepreg layers, although it is possible to provide a layer stack of (e.g. alternating) electrically insulating layers and electrically conductive layers, for example copper coated resin layers and/or copper coated prepreg layers. The number of the layers may be selected as desired for specific approaches. It is also possible to provide one single prepreg layer as component carrier body 210.

(13) As can be seen, the electronic device 200 differs from that of FIG. 1 in that the adhesive structure 230 covers only a first part 260 of one surface of the electronic device 250. This said surface is the lower main surface of the electronic component 250 according to FIG. 2. The remaining second part 270 of the surface is covered with material of the component carrier body 210, e.g. with resin. In particular, in the shown embodiment, the remaining second part 270 of the electronic component 250 includes edge sections 270 of the electronic component 250. For example, at least one edge section 270 of the electronic component 250 is free from the adhesive structure 230 and covered with electrically insulating material 210-1 of the component carrier body 210. By keeping the edge sections free from adhesive structure, the formation of the meniscus 130-1 of FIG. 1, can be avoided. Thus, adjacent electronic components 250 can be placed closer together.

(14) Furthermore, the adhesive structure 230 comprises vias 240 for electrically contacting the embedded electronic component 250 with the electrically conductive layer 220. Preferably, the aspect ratio of the via is d=1.4h, where d is the diameter of the via 240 and h is the thickness of the adhesive structure 230.

(15) FIG. 3 shows for the better understanding of the invention a conventional electronic device 300 with a conventional thick adhesive layer 130. The lower surface and the lateral surfaces of the electronic component 150 are covered with the conventional thick adhesive layer 130. Conventional vias 340 are formed in the adhesive layer 130 for contacting the electronic component 150. If an aspect ratio of d=1.4h is desired, where d is the diameter of the conventional via 340 and h is the thickness of the conventional adhesive layer 130, the conventional thick adhesive layer 130 necessitates a comparatively large diameter d, as becomes apparent from the above formula. A large via diameter permits only a small registration tolerance x.

(16) As can be seen from the FIG. 2, by keeping the thickness of the adhesive structure 230 small, the diameter d of the via can also be kept small. In contrast to this, as can be taken from FIG. 3, a conventional adhesive layer 130 requires a larger via diameter d.

(17) FIG. 4a and FIG. 4b show the manufacturing process of an electronic device 200 according to an embodiment of the invention. As electrically conductive layer 220, a copper foil 220 with registration marks (not shown) is provided. Then, the adhesive structure 230 is arranged above the copper foil 220 using the registration marks for an exact alignment. In this embodiment, the adhesive structure comprises adhesive sub-structures 430 which are spatially separated from each other. As can be seen, the adhesive structure is thinner than that of FIG. 3.

(18) The electronic component 250 is placed on the adhesive sub-structures 430 using the registration marks. FIG. 4a shows the resulting intermediate product state. In a subsequent manufacturing step, FR4 as component carrier body 210 is laminated on the electronic component 250, thereby filling the space between the adhesive sub-structures 430 with resin from the FR4 layer. A further copper foil 420 is subsequently laminated on the component carrier body 210. FIG. 4b shows the final electronic device 200 according to an exemplary embodiment.

(19) FIG. 5 is a plan view of the adhesive sub-structures 430 according to the exemplary embodiment shown in FIGS. 4a and 4b. The adhesive structure 230 comprises five circular adhesive sub-structures 430 arranged on the copper foil 220.

(20) FIG. 6a shows an electronic component 250 to be adhered to the electrically conductive layer. FIG. 6b to FIG. 6g show possible arrangements of adhesive sub-structures 430 according to an exemplary embodiment of the invention. In particular, FIG. 6b shows an arrangement of three rectangular adhesive sub-structures 430 arranged substantially parallel to each other. FIG. 6c shows an arrangement wherein the adhesive sub-structures are arranged as a 44 array of substantially square adhesive sub-structures 430. FIG. 6d shows a square adhesive substructure 230 with two rectangular cavities therein. FIG. 6e shows an arrangement of circular adhesive sub-structures 430 which are arranged like a 22 array with an additional circular sub-structure 430 in the center. It is also possible to arrange the adhesive sub-structures 430 e.g. as a 33 array (FIG. 6f) or a 22 array (FIG. 6g).

(21) FIG. 7 shows a classification table for the Moisture Sensitivity Level Test. As described above, in conventional electronic devices 100 with comparatively huge amount of adhesive, moisture diffuses from the environment into the adhesive material, thereby leading to a declined life duration and/or delamination in subsequent manufacturing steps. It has turned out that electronic devices according to an exemplary embodiment of the present invention achieve better results in MSL Testing due to the reduced amount of adhesive material.

(22) FIG. 8 shows different types of vias employed in electronic devices 200 for electrical connection through the layers. As explained above, providing an adhesive structure 230 with a substantially constant thickness in a range between 3 m to 300 m (310.sup.6 m to 30010.sup.6 m) enables to keep the diameter of the vias through the adhesive structure 230 small. This applies for via types like centered microvias, off-centered microvias, microvias partially arranged inside a pad, plugged microvias, dog-bone microvias, partially filled microvias, completely filled microvias and for all further known types of vias. For a reliable electrical connection through the via, a homogenous distribution of filling material inside the via is important. It has turned out, that by providing the via with an aspect ratio of d=1.4h (where d is the diameter of the via and h is the thickness of the adhesive structure), the deposition of material inside the via, for example copper, occurs homogenous and free of voids. Void formation is a growing problem in manufacturing of component carriers due to increase of miniaturization, since actually the occurrence of small voids may decrease the conduction of electrical signals through the via. Providing an electronic device with the mentioned aspect ratio prevents void formation and thus provides an improved signal integrity.

(23) FIG. 9 shows a bar diagram showing the void formation reported for each of the microvia designs of FIG. 8. The ordinate of the diagram represents the occurrence of voids in percent. Along the abscissa, the different microvia designs are represented, wherein respectively the left bar represent the voiding for a 0.5 mm Chip Scale Package (CSP), the center bar represents the voiding for a 0.8 mm CSP and the right bar represents the voiding for a 1.0 mm Ball Grid Array (BGA).

(24) It should be noted that the term comprising does not exclude other elements or steps and the a or an does not exclude a plurality. Also elements described in association with different embodiments may be combined.

(25) Implementation of the invention is not limited to the preferred embodiments shown in the figures and described above. Instead, a multiplicity of variants are possible which use the solutions shown and the principle according to the invention even in the case of fundamentally different embodiments.

LIST OF REFERENCE SIGNS

(26) 100 conventional electronic device 110 conventional component carrier body 110-1, 110-2 conventional further layers of component carrier body 120 conventional electrically conductive layer 130 conventional adhesive structure 130-1 conventional meniscus 150 conventional electronic component 200 electronic device 210 component carrier body 210-1, 210-2, 210-3 further layers of component carrier body 220 electrically conductive layer 230 adhesive structure 240 via 250 electronic component 260 first part of the surface of the electronic component 270 remaining second part of the surface 300 conventional electronic device 340 conventional via 420 further copper foil 430 adhesive sub-structure