This application claims the foreign priority benefit under 35 U.S.C. Section 119 of Korean Patent Application Serial No. 10-2013-0058965, filed on May 24, 2013, in the Korean Intellectual Property Office, which is hereby incorporated by reference in its entirety into this application.
1. Field
Embodiments of the present invention relate to an electronic component embedded printed circuit board and a method for manufacturing the same.
2. Description of the Related Art
As the size of substrates are limited and multiple functions of electronic devices are required with the miniaturization and thinning of IT electronic devices, such as mobile phones, there is a need to mount electronic components for implementing more functions in the limited area of substrates.
However, as the size of a substrate is limited, since it is not possible to secure a sufficient mounting area of the electronic components, there is a demand for technologies for inserting electronic components such as active devices like ICs and semiconductor chips and passive devices in a substrate, and technologies for embedding active devices and passive devices in the same layer or embedding electronic components in a substrate by stacking them have been developed.
In recent times, as high performance is required according to the popularization of devices such as smartphones having video conferencing and LTE technology, tablet PCs, etc. and the high speed signal transmission is frequent, a technology of embedding two or more electronic components such as MLCCs, which reduce the distortion and noise of the transmitted signals in transmitting a large amount of data, rather than only one electronic component, is needed.
In order to embed a plurality of electronic components as mentioned above, a cavity (space) for embedding one or more electronic components is required to be formed in a core of a substrate, and various types of defects may occur in the process of attaching a carrier (tape, film) for fixing the electronic component to the bottom of the cavity, fixing the electronic component, forming an insulating layer thereon, or removing the carrier.
Japanese Patent Laid-open Publication No. 2009-070938
One aspect of the present invention is to overcome the above-described problems and to provide an electronic component embedded printed circuit board that can improve productivity and product yield by embedding a plurality of electronic components as one unit.
Another aspect of the present invention is to provide a method for manufacturing an electronic component embedded printed circuit board that can improve productivity and product yield by embedding a plurality of electronic components as one unit.
In accordance with one aspect of the present invention, there is provided an electronic component embedded printed circuit board including: a core having a cavity formed therein; an electronic component unit embedded in the cavity and having a coating layer formed on the outer peripheral surface thereof to fix a plurality of electronic components; insulating layers laminated on the top and bottom of the core having the electronic component unit embedded therein; and outer layer circuit patterns formed on the insulating layers.
The electronic component unit may include two or more bonded electronic components which are horizontally or vertically arranged at predetermined intervals in the coating layer.
The core may be formed by impregnating a fabric with an epoxy material or impregnating a fabric with a glass material.
Meanwhile, the coating layer of the electronic component unit may be made of an organic/inorganic composite resin and the electronic components are bonded at predetermined intervals by the coating layer, wherein the coating layer may be formed on the top and bottom surfaces of the electronic components or formed to cover the entire surface of the electronic components.
And, the organic/inorganic composite resin may prepared by including a filler in a polymer resin, wherein the polymer resin may be a resin material mixed with one or more resins selected from epoxy, BT resins, acryl, polyimide (PI), polystyrene (PS), polyethersulfone (PES), and liquid crystal polymer (LCP)and the impregnated filler is an inorganic ceramic filler selected from SiO2, Ba2SO4, and Ralc.
And, the surface of the coating layer of the electronic component unit may have a microroughness in the range of about 0.01 to about 0.99 μm.
Meanwhile, in accordance with another aspect of the present invention, there is provided a method for manufacturing an electronic component embedded printed circuit board, including: forming a cavity in a core and attaching a carrier to the bottom surface of the core; inserting an electronic component unit having a plurality of electronic components fixed by a coating layer in the cavity; forming an upper insulating layer on the top of the core having the electronic component unit embedded therein; removing the carrier attached to the bottom surface of the core; forming a lower insulating layer on the opposite surface of the core having the upper insulating layer formed thereon; and forming a via in the upper and lower insulating layers and forming outer layer circuit patterns which are electrically connected to the plurality of electronic components constituting the electronic component unit through the via.
In accordance with another aspect of the present invention, an electronic component embedded printed circuit board includes: a core having a cavity formed therein; an electronic component unit embedded in the cavity, comprising a plurality of electronic components and a coating layer encapsulating the plurality of electronic components; and an insulating layer laminated at least on a top of the core.
These and/or other aspects and advantages of the present general inventive concept will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
A matter regarding to an operational effect including a technical configuration for an object of an electronic component embedded printed circuit board and a method of manufacturing the same in accordance with the present invention will be clearly appreciated through the following detailed description with reference to the accompanying drawings showing embodiments of the present invention.
First,
As shown, an electronic component embedded printed circuit board 100 in accordance with an embodiment of the present invention may include a core 110 having a cavity 113, an electronic component unit 200 embedded in the cavity 113 and having a plurality of horizontally connected electronic components 210; an insulating layer 120 laminated on the top and bottom of the core 110; and an outer layer circuit pattern (not shown in the drawing) formed on the insulating layer 120.
In the electronic component embedded printed circuit board 100, although it is shown that the electronic component unit 200 embedded in the core 110 is embedded in one place, without being limited thereto, it means that the electronic component unit 200 is embedded in a printed circuit board of each unit at regular intervals.
The core 110 may be made of an insulating material and may have inner layer circuit patterns 111 patterned on top and bottom surfaces thereof. The inner layer circuit patterns 111 may be electrically conducted to the outer layer circuit patterns of the insulating layers 120a and 120b through a via hole or a through hole 112 formed through the core 110. Further, the core 110, which is made of an insulating material, may be formed by impregnating a fabric with an epoxy material or impregnating a fabric with a glass material to improve strength. The cavity 113 may be formed to pass through the top and bottom of the core 110. The cavity 113 may be formed to pass through the top and bottom of the core 110 by mechanical drilling or laser drilling like a via. At this time, it is preferred that the cavity 113 is formed to have a width equal to or greater than that of the electronic component unit 200 inserted therein. And since the electronic component unit 200 inserted in the cavity 113 has a structure in which the plurality of electronic components 210 are connected to each other unlike the prior art, the cavity 113 can be formed wider than the prior art.
Meanwhile, as shown in
Here, when the coating layer 220 is formed on the top and bottom surfaces of the electronic components 210, the organic/inorganic composite resin is coated on the top and bottom surfaces of the plurality of electronic components 210 which are arranged horizontally through thermal compression by top and bottom pressing so that the coating layer 220 can be formed only on the top and bottom surfaces of the electronic components 210. And when the coating layer 220 is formed on the entire surface of the electronic components 210, the coating layer 220 is formed to cover the entire outer peripheral surface of the electronic components 210 by applying and curing the organic/inorganic composite resin on the entire surface of the plurality of electronic components 210, which are maintained horizontally, and maintaining the organic/inorganic composite resin with a predetermined thickness by chemical desmearing. At this time, it is preferred that the height of the electronic component unit 200 in which the coating layer 220 covers the plurality of electronic components 210 is equal to or lower than the height of the core 110.
The coating layer 220 has a CTE, that is, a coefficient of thermal expansion, by curing of the organic/inorganic composite resin. It is preferred that the organic/inorganic composite resin material and containing materials of the coating layer 220 are adjusted to obtain a CTE similar to that of the core 110. Accordingly, the electronic component unit 200 in which the plurality of electronic components 210 are covered with the coating layer 210 can be embedded in the cavity 113 of the core 110 to have the same direction and degree of bending when the core 110 is bent.
Further, the organic/inorganic composite resin, which constitutes the coating layer 220 of the electronic component unit 200, may be prepared by including a filler in a polymer resin. Typically, the polymer resin may be a resin material mixed with one or more polymer resins selected from epoxy, BT, acryl, PI, PS, PES, and LCP, and the filler included in the organic/inorganic composite resin may be an inorganic ceramic filler selected from SiO2, Ba2SO4, and Ralc. At this time, the content of the filler impregnated in the resin material constituting the organic/inorganic composite resin may be about 20 wt % to about 60 wt %.
And, two or more electronic components 210, which constitute the electronic component unit 200, may be fixed by the coating layer 220 to be embedded in the core 110 at regular intervals according to the design specifications of the electronic component embedded in the printed circuit board.
Further, a roughness may be formed on the surface of the coating layer 220 of the electronic component unit 200. The roughness may be a microroughness formed on the film of the coating layer 220, and it is preferred that the roughness Ra is formed in the range of 0.01 to 0.99 μm. It is possible to improve adhesion with the insulating layers 120a and 120b by the roughness formed on the surface of the coating layer 220 of the electronic component unit 200.
Meanwhile, the insulating layers 120a and 120b may be laminated on the top and bottom surfaces of the core 110 in which the electronic component unit 200 is embedded in the cavity 113. The insulating layers 120a and 120b may be made of prepreg consisting of an epoxy resin material and silica or an ABF film. As described above, since the organic/inorganic composite material, which constitutes the coating layer 220 of the electronic component unit 200 embedded in the cavity 113 of the core 110, is the same/similar material as the insulating layers 120a and 120b, it is possible to secure high adhesion on the adhesive interface between the coating layer 220 and the insulating layers 120a and 120b and perform stable via processing design and good copper plating when processing a via using laser.
The outer layer circuit patterns may be formed on the insulating layers 120a and 120b. The outer layer circuit patterns may be electrically connected to the inner layer circuit patterns 111 formed on the core 110 through vias 121 formed in the insulating layers 120a and 120b. This outer layer circuit pattern may be regarded as an inner layer circuit pattern again when another insulating layer is further built up on the insulating layer 120 and electrically connected to the pattern on the finally formed outermost insulating layer through the vias.
Further, among the vias 121, the via 121 formed in the insertion position of an MLCC, which is a passive device constituting the electronic component unit 200, electrically connects the outer layer circuit pattern and an external electrode of the MLCC and in contact with the external electrode of the MLCC through the insulating layers 120a and 120b and the coating layer 220 of the electronic component unit 200.
The connection of the patterns between the core 110 and the insulating layer 120 and between the insulating layers may be typically performed through the via 121, and the vias may be typically formed by mechanical drilling using CNC or laser drilling.
The printed circuit board 100 of the present embodiment configured as above can improve productivity compared to the prior art in which one electronic component is inserted in the cavity by forming the coating layer on the outer peripheral surface of the plurality of passive devices, typically such as MLCCs, and embedding the passive devices in the core and prevent a dimple phenomenon that the insulating layer is depressed between the electronic components by easily embedding the electronic components than the case in which one electronic component is inserted and flattening the surface by the coating layer 220.
Although it is mainly described that the electronic component embedded printed circuit board in accordance with an embodiment of the present invention described above has a structure in which the electronic components 210 constituting the electronic component unit 200 embedded in the core 110 are horizontally arranged by the coating layer 220, when only the size of the printed circuit board is a main design target beyond the purpose of thinning the printed circuit board, the plurality of electronic components may be laminated vertically and the laminated electronic components may be fixed at regular intervals by the coating layer to be embedded in the cavity of the core. Of course, in this case, it is preferred that the thickness of the core is as large as the height of the laminated electronic components.
A method for manufacturing the electronic component embedded printed circuit board for embodiments of the present invention configured as above will be described with reference to the following drawings.
First, as shown in
Additionally, a carrier C may be attached to the bottom surface of the core 110 as in
Next, as shown in
Meanwhile, before inserting the electronic component unit 200 in the core 110, the plurality of electronic components 210 are arranged horizontally and the outer peripheral surface thereof is fixed by the coating layer 220 using an organic/inorganic composite resin. That is, referring to
When the coating layer 220 is formed on the top and bottom surfaces of the electronic components 210, the coating layer 220 is formed by coating the organic/inorganic composite resin on the top and bottom surfaces of the electronic components 210 and performing thermal compression using a press, and when the coating layer 220 is formed on the entire surface of the electronic components 210, the coating layer 220 is formed with a predetermined thickness by curing the organic/inorganic composite resin on the entire outer peripheral surface of the electronic components 210 and performing chemical desmearing. At this time, during the chemical desmearing of the coating layer 220, a predetermined microroughness may be formed on the surface film of the coating layer 220. Here, when forming the coating layer on the entire or a part of the surface of the electronic components 210, the organic/inorganic composite resin coating layer 220 may be formed to cover the surface of the electronic components 210 by horizontally positioning the plurality of electronic components 210 in a specific frame and injecting the organic/inorganic composite resin between the electronic components 210.
At this time, it is preferred that the organic/inorganic composite resin constituting the coating layer 220 has the same/similar CTE as the core 110 by containing a predetermined amount of filler in a resin material mixed with one or more polymer resins selected from epoxy, BT resins, acryl, polyimide (PI), polystyrene (PS), polyethersulfone (PES), and liquid crystal polymer (LCP), and the organic/inorganic composite resin has a CTE similar to that of the insulating layer 120, which will be described later, to improve bonding reliability and bending characteristics.
Next, as shown in
And, when the lamination of the upper insulating layer 120a is completed, the carrier C attached to the bottom surface of the core 110 is removed as in
Finally, as in
As described above, the electronic component embedded printed circuit board and the method for manufacturing the same in accordance with the present invention can improve productivity compared to the prior art in which one electronic component is inserted in the cavity by forming the coating layer on the outer peripheral surface of the plurality of electronic components and embedding the electronic components in the core and prevent deviation of the electronic components or voids between the electronic components and a dimple phenomenon that the insulating layer is depressed due to deviation or voids.
Further, the present invention can reduce manufacturing costs by embedding the plurality of electronic components in the form of one unit to simplify manufacturing processes and can improve a product yield by sorting only the good components in advance to embed the good components in the core.
And, the present invention can bring the coating layer and the insulating layer in direct contact with each other by filling a part of the insulating layer in the cavity to be introduced into the space between the electronic component unit embedded in the cavity and the sidewall of the cavity when forming the insulating layer, thereby improving the adhesion between the insulating layer and the electronic component unit.
The term “entire surface,” when used to describe the surface on which the coating layer is formed, does not exclude, for example, the absence of the coating layer at certain areas for purposes of connection elements such as via holes.
The above-described embodiments of the present invention are disclosed for the purpose of exemplification and it will be appreciated by those skilled in the art that various substitutions, modifications and variations may be made in these embodiments without departing from the technical spirit of the present invention. Such substitutions and modifications are intended to be included in the appended claims.
Number | Date | Country | Kind |
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10-2013-0058965 | May 2013 | KR | national |