Patent Application
20140153204
Claim and incorporate by reference domestic priority application and foreign priority application as follows:
This application claims the benefit under 35 U.S.C. Section 119 of Korean Patent Application Serial No. 10-2012-0138044, entitled filed Nov. 30, 2012, which is hereby incorporated by reference in its entirety into this application.
1. Field of the Invention
The present invention relates 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 is limited and multiple functions of electronic devices are required with the miniaturization and thinning of the IT electronic devices including mobile phones, it is required to mount electronic components for implementing more functions in the limited area of the substrate.
However, as the size of the substrate is limited, since it is not possible to secure a sufficient mounting area of the electronic components, there is a demand for a technology of inserting electronic components like active devices, such as ICs and semiconductor chips, and passive devices in a substrate. In recent times, a technology of embedding active devices and passive devices in the same layer or a technology of embedding active devices and passive devices in a substrate by stacking them has been developed.
Typically, a method for manufacturing an electronic component embedded printed circuit board forms a cavity in a core of a substrate and inserts electronic components such as various devices, ICs, and semiconductor chips in the cavity. After that, a resin material such as prepreg is applied inside the cavity and on the core in which the electronic component is inserted to form an insulating layer as well as to fix the electronic component, and a via hole or a through hole is formed in the insulating layer and a circuit is formed by plating to allow the electronic component to conduct with the outside of the substrate.
At this time, a circuit pattern is formed inside and on the via hole or the through hole by plating to be used as an electrical connection means with the electronic component embedded in the substrate, and a multilayer printed circuit board in which the electronic component is embedded can be manufactured by sequentially laminating the insulating layer on upper and lower surfaces of the substrate.
In the conventional electronic component embedded printed circuit board like this, since soldering and reflow processes are repeated in every manufacturing process, a high temperature heat is applied to the laminate, and warpage of the substrate may occur whenever heating the laminate at high temperature. At this time, as the electronic component embedded in the substrate is made of a material having a different coefficient of thermal expansion (CTE) from the insulating layer bonded to the outside thereof, stress is concentrated on the bonding interface with the insulating layer due to repetition of the warpage of the substrate in every heating process, and as the process proceeds, delamination or lifting of the bonding interface occurs due to thermal shock.
The present invention has been invented in order to overcome the above-described problems and it is, therefore, an object of the present invention to provide an electronic component embedded printed circuit board with improved mechanical characteristics and reliability.
It is another object of the present invention to provide a method for manufacturing an electronic component embedded printed circuit board with improved mechanical characteristics and reliability.
In accordance with one aspect of the present invention to achieve the object, there is provided an electronic component embedded printed circuit board including: a core having a cavity; an electronic component inserted in the cavity and having a bonding coating layer on an outer peripheral surface; insulating layers laminated on and under the core and in contact with the bonding coating layer; and circuit patterns provided on the insulating layers.
At this time, the electronic component may include external electrodes provided on both sides and a main body provided between the external electrodes, and the bonding coating layer may be formed over the entire surface along the external electrodes and the main body or on a surface of the main body except the external electrodes.
Further, the bonding coating layer may include a coupling agent interposed between different kinds of materials to reinforce a bonding force, and the coupling agent may include silane containing silicon (Si) atoms and organic functional groups. And, the silane may include at least one selected from the group consisting of amino silane, epoxy silane, and vinyl silane.
Further, the silane may be used by being mixed with ethanol.
And, a via may be further included inside the insulating layer to electrically connect the circuit pattern and the external electrode, the insulating layer may fill a space between the cavity and the electronic component, and circuit layers of a predetermined pattern may be formed on upper and lower surfaces of the core to be electrically connected through a through hole.
Meanwhile, in accordance with another aspect of the present invention to achieve the object, there is provided a method for manufacturing an electronic component embedded printed circuit board, including the steps of: forming a through hole-shaped cavity in a core and attaching a carrier to a lower surface of the core; inserting an electronic component having a bonding coating layer on an outer peripheral surface in the cavity; forming an upper insulating layer on the core in which the electronic component is embedded; removing the carrier attached to the lower surface of the core and reversing the core; forming a lower insulating layer on an opposite surface of the core on which the upper insulating layer is formed; and forming circuit patterns on the upper and lower insulating layers to be electrically connected to the electronic component through a via.
And, in accordance with another aspect of the present invention to achieve the object, there is provided a method for manufacturing an electronic component embedded printed circuit board, including the steps of: forming a through hole-shaped cavity in a core and attaching a carrier to a lower surface of the core; inserting an electronic component in the cavity; forming a bonding coating layer on the electronic component inserted in the cavity; forming an upper insulating layer on the core in which the electronic component is embedded in the cavity; removing the carrier attached to the lower surface of the core and reversing the core; forming the bonding coating layer on a surface of the electronic component exposed on the cavity of the core, where the bonding coating layer is not formed; forming a lower insulating layer on an opposite surface of the core on which the upper insulating layer is formed; and forming circuit patterns on the upper and lower insulating layers to be electrically connected to the electronic component through a via.
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 preferable embodiments of the present invention.
Electronic Component Embedded Printed Circuit Board
First,
As shown, in an electronic component embedded printed circuit board 100 in accordance with the present invention, an electronic component 200 may be embedded inside a core 110 having a cavity 111, insulating layers 120 may be laminated on and under the core 110, and a bonding coating layer 210 may be formed on an outer peripheral surface of the electronic component 200.
In the electronic component embedded printed circuit board 100, although it is shown that the electronic component 200 embedded in the core 110 is embedded in one place, it is not limited thereto. The electronic component 200 may be embedded in a printed circuit board of each unit at regular intervals, and one or more electronic components 200 may be embedded according to the type of the embedded electronic component.
The cavity 111 may be formed in the core 110, which is positioned in the center of the electronic component embedded printed circuit board 100, in the shape of a through hole, and the cavity 111 may be formed by laser processing or drilling using CNC. At this time, it is preferred that the cavity 111 is formed to have a width equal to or greater than that of the electronic component 200 inserted therein.
Further, circuit layers 112 may be formed on upper and lower surfaces of the core 111 in a predetermined pattern, respectively, and the respective circuit layers 112 may be electrically connected through a via or a through hole 113 passing through the core 110. At this time, the core 110 may be generally made of an insulating material but may be made of a metal material such as aluminum to improve heat radiation efficiency of a substrate. When forming a metal core, an insulating layer should be further formed to prevent a short before formation of a circuit layer.
Meanwhile, the electronic component 200 is inserted in the cavity 111 of the core 110. The electronic component 200 may be an active device such as IC, semiconductor chip, or CPU in addition to a passive device such as MLCC or LTCC. At this time, it is preferred that a height of the electronic component is equal to that of the core.
Here, describing the electronic component 200 by taking an MLCC shown in the drawing as an example, an internal electrode may be formed in a main body 201, positive and negative external electrodes 202 may be formed on both sides of the main body 201, and the external electrodes 202 on the both sides may be physically and electrically connected to external circuits, respectively.
The bonding coating layer 210 may be formed on the outer peripheral surface of the electronic component 200. The bonding coating layer 210 may be made of a material containing silicon (Si) atoms and organic functional groups, and typically, silane may be used. The bonding coating layer 210 serves as a chemical coupling agent that improves bonding performance between different kinds of materials of the insulating layer 120 formed on the outer peripheral surface of the electronic component 200 and the both surfaces of the core 110 and prevents delamination and lifting of the insulating layer regardless of warpage and thermal shock repeated when processing the printed circuit board by reinforcing adhesion of the insulating layer 120 on the outer peripheral surface of the electronic component 200.
The bonding coating layer 210 may be formed only on the outside of the main body 201 of the electronic component 200, that is, the MLCC and may be formed on the entire outer peripheral surface of the electronic component 200 including outer peripheral surfaces of the external electrodes 202 provided on the both sides of the main body 201 according to a forming method thereof.
Here, the method of forming the bonding coating layer 210 on the electronic component 200 embedded in the cavity 111 of the core 110 may be various. Typically, the bonding coating layer 210 may be formed on the outer peripheral surface of the electronic component 200 by dipping the electronic component 200 in a silane solution and drying the electronic component 200 before embedding the electronic component 200 in the core 110 or the bonding coating layer 210 may be formed by embedding the electronic component 200 in the core 110 first, applying the silane solution on the surface of the electronic component 200 through printing, spraying, or dispensing, and drying the electronic component 200. At this time, when forming the bonding coating layer 210 on the outer peripheral surface of the electronic component 200 by dipping first, the bonding coating layer 210 may be formed after forming the external electrode 202 in the electronic component 200 or the bonding coating layer 210 may be formed on the outer peripheral surface of the main body 201 before forming the external electrode 202 and then the external electrode 202 may be formed. Therefore, when forming the bonding coating layer 210 before forming the external electrode 202, the bonding coating layer 210a may be formed only on the outside of the main body 201 between the external electrodes 202 of the electronic component 200 as shown in
The insulating layers 120 may be respectively formed on and under the core 110 in which the electronic component 200 is embedded. The insulating layer 120 may be formed by laminating and curing an insulating material, that is, an insulating resin material such as prepreg. A portion in contact with the outer peripheral surface of the electronic component 200 when laminating and curing the insulating layer 120 may be firmly adhered to the insulating layer 120 through the bonding coating layer 210 formed in the shape of a thin film or absorbed on the outer peripheral surface of the electronic component 200. At this time, when the bonding coating layer 210 is also formed on the surface of the both external electrodes 202 of the electronic component 200, the both surfaces of the electronic component 200 may be also closely coupled with the insulating layer 120.
A plurality of vias 121 may be formed in the insulating layer 120. The via 121 may be formed by laser processing or drilling using CNC similarly to the cavity 111 formed in the core 110. A circuit pattern 130, which is electrically connected to the electronic component 200, may be formed by forming a plating layer on the upper surface of the insulating layer 120 including the via after forming the via 121 and etching the plating layer.
The electronic component embedded printed circuit board 100 configured like this can improve bonding performance between the outer peripheral surface of the electronic component 200 and the insulating layer 120 by interposing the bonding coating layer 210 on a contact interface of the surface of the electronic component 200 embedded in the core 110 and the insulating layers 120 formed on and under the core 110.
Embodiment of Method for Manufacturing Electronic Component Embedded Printed Circuit Board
A method for manufacturing the electronic component embedded printed circuit board of the present invention configured as above will be described with reference to the following drawings.
First,
First, as shown in
Additionally, a carrier C may be attached to a lower surface of the core 110. The carrier C, which is a member for fixing a position of the electronic component 200 when inserting the electronic component 200 in the cavity 111 formed as a through hole, prevents the electronic component 200 from being separated from the cavity 111 and temporarily fixes the electronic component 200 by an adhesive member applied on an upper surface thereof.
Next, the electronic component 200 is inserted in the cavity 111 of the core 110 to be positioned on the carrier C. It is preferred that the electronic component 200 is an electronic component having the same height as the thickness of the core 110. When the height of the electronic component 200 is higher than the thickness of the core 110, it is needed to increase the thickness of the core 110 to make the same height.
Meanwhile, a bonding coating layer 210 is applied on an outer peripheral surface of the electronic component 200 before inserting the electronic component 200 in the core 110 and cured. The bonding coating layer 210 may be formed on the entire or a portion of the outer peripheral surface of the electronic component 200. That is, describing with reference to
At this time, the bonding coating layer 210 is a material for chemically coupling an organic material and an inorganic material which are different kinds of materials and may include silane containing silicon atoms and organic functional groups coupled thereto. Silane is a monomer and there are various types of products according to organic groups coupled to Si—O that are mainly used for the purpose of processing various powder and increasing adhesion of a resin. Particularly, as the bonding coating layer 210 is formed of silane on the surface of an MLCC, which is formed by sintering powder, as the electronic component applied to the present embodiment, it is possible to increase adhesion between the surface of the electronic component 200 and the inorganic material, water repellency, and resin flow.
Here, in forming the bonding coating layer 210 on the surface of the electronic component 200, when forming the bonding coating layer 210 only on the surface of the main body 201 of the electronic component 200, the bonding coating layer 210 is formed only on the exposed portions of the upper and lower surfaces of the main body 201 as shown in
Next, as in
And, when the lamination of the upper insulating layer 120a is completed, the carrier C attached to the lower surface of the core 110 is removed. After that, as in
Finally, as in
Another Embodiment of Method for Manufacturing Electronic Component Embedded Printed Circuit Board
As shown, first, a cavity 111 is formed in a core 110, which is made of an insulating material, in the shape of a through hole. At this time, the conditions of formation or size of the cavity 111 may be equal to the core processing conditions in the embodiment shown in
Next, a carrier C is attached to a lower surface of the core 110, and an electronic component 200 is inserted in the cavity 111 formed in the core 110 to be fixed on the carrier C. Here, the electronic component 200 inserted in the cavity 111 of the core 110 is an electronic component in which only external electrodes 202 are formed on both sides of a main body 201 and a bonding coating layer 210 is not formed on an outer peripheral surface.
After inserting the electronic component 200, a silane solution is applied on the electronic component 200 by spraying, printing, or dispensing. At this time, in
Next, as in
After that, as in
And, a lower insulating layer 120b is laminated on an opposite surface of the core 110 on which the upper insulating layer 120a is formed in the same manner as the upper insulating layer 120a and cured by heating and compression to form the upper and lower insulating layers 120a and 120b as in
Finally, as in
Evaluation of Bonding Force of Electronic Component of Electronic Component Embedded Printed Circuit Board
Bonding reliability of the electronic component of the electronic component embedded printed circuit board manufactured as in
Evaluation of Adhesion Between Electronic Component and Insulating Layer
First, after prepreg (PPG), which is used as a representative material of the insulating layer 120 adhered to the electronic component 200 embedded in the electronic component embedded printed circuit board in accordance with the present invention, and the MLCC (electronic component), which has the bonding coating layer 210 on the outer peripheral surface, are bonded and the prepreg is cured to closely couple the insulating layer and the MLCC, evaluation is performed by applying a shear stress according to the standard specifications of JESD22-B117.
As the result of the evaluation by the above specifications, as shown in the graph of
Further, it is possible to understand that the shear strength of the MLCC having the bonding coating layer 210 formed by applying a silane solution in which epoxy silane or vinyl silane in addition to amino silane is mixed with ethanol is improved by about 20 to 30%.
Here,
Evaluation of Bonding Reliability of Electronic Component Embedded in Printed Circuit Board
In the electronic component embedded printed circuit board manufactured through the manufacturing method of the present invention, evaluation of bonding reliability of the electronic component embedded in the substrate and the insulating layer is performed by a bending test according to JESD22-B113 standard specifications as shown in
As the result of the evaluation by the above specifications, delamination of the electronic component 200 and the insulating layer 120 is checked through an ultrasonic microscope by comparing the printed circuit board in which the electronic component 200 having the bonding coating layer 210 is embedded with the printed circuit board in which the electronic component 200 without the bonding coating layer 210 is embedded.
Further, as shown in Table 1, looking into the results of the bending test when the bonding coating layer is formed on the electronic component, when the bonding coating layer is not formed on the electronic component, and when the bonding coating layer is formed on the electronic component by spraying (another embodiment, corresponding to a process of
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 bonding and adhesion performances of the insulating layers laminated on and under the core and the surface of the electronic component by forming the bonding coating layer on the surface of the electronic component embedded in the core to embed the electronic component, and can prevent substrate failures and improve the yield of the printed circuit board products by improving coupling performance of the insulating layer and the electronic component to prevent delamination and lifting of the insulating layer from the electronic component.
The above-described preferred 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 |
|---|---|---|---|
| 10-2012-0138044 | Nov 2012 | KR | national |
