Patent Grant
11510311
The present disclosure relates to an electronic component module and a method for manufacturing an electronic component module, and more specifically to a shielding technology in a device in which electronic components are mounted on both surfaces of a board.
An electronic device (module) in which electronic components are mounted on both surfaces of a board has been known. In such a module, electromagnetic waves are radiated to the outside from the mounted electronic components, or the electromagnetic waves reach from the outside. Thus, an operation of the module may be influenced.
As a method for suppressing the influence of such electromagnetic waves, a technology for suppressing the leaking of the electromagnetic waves generated in the electronic components to the outside of the electronic device or the reaching of the electromagnetic waves from the outside by covering a periphery of the electronic device with a shield is adopted.
U.S. Pat. No. 9,935,083 (Patent Document 1) discloses a configuration of an electronic device having electronic components such as semiconductors mounted on both surfaces of a board. In the configuration, electromagnetic interference (EMI) is suppressed by molding the electronic components on the board with resin and forming a shield in the periphery of the molded board.
In the configuration disclosed in U.S. Pat. No. 9,935,083 (Patent Document 1), the electromagnetic waves generated in the electronic components in the electronic device can be prevented from being radiated to the outside by the shield, and the influence of the electromagnetic waves from the outside on the mounted electronic components can be reduced.
Patent Document 1: U.S. Pat. No. 9,935,083
On the other hand, as in U.S. Pat. No. 9,935,083 (Patent Document 1), in the case of the configuration in which the electronic components are mounted on both the surfaces of the board and the entire board including any surface of both the surfaces and a plurality of side surfaces connecting both the surfaces is covered with the shield, there is a possibility that the electromagnetic waves radiated from the electronic components mounted on one surface (front surface) of the board are transmitted to the other surface (back surface) of the board with the shield disposed in the periphery of the board interposed therebetween and influence on the electronic components on the back surface side.
The present disclosure has been made to solve such a problem, and an object thereof is to provide a shield structure capable of effectively suppressing the influence of electromagnetic waves in an electronic component module in which electronic components are mounted on both surfaces of a board.
An electronic component module according to the present disclosure includes a module board, electronic components, mold portions, and a shield. The module board has a first surface, a second surface facing the first surface, and side surfaces connecting the first surface and the second surface. The electronic components are mounted on at least one of the first surface and the second surface. The mold portions cover the electronic components. The shield covers at least a part of the mold portions and the side surfaces. Protrusions protruding from the side surfaces of the module board are formed on the module board. The shield is separated by the protrusions.
In the electronic component module according to the present disclosure, it is possible to prevent the electromagnetic waves radiated from the device disposed on the front surface side of the board from being transmitted to the electronic components mounted on the back surface with the shield interposed therebetween. Accordingly, in the electronic component module in which the electronic components are mounted on the board, the influence of the electromagnetic waves can be effectively suppressed.
Each of
Each of
Each of
Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The same or corresponding portions in the drawings are designated by the same reference symbols and the description thereof will not be repeated.
[Configuration of Electronic Component Module]
The module board 10 has a multi-layer structure, and is formed by a resin board such as a glass epoxy resin or a liquid crystal polymer, or a ceramic board such as low temperature co-fired ceramics (LTCC). Conductor patterns 80 for forming wiring patterns, ground electrodes, inductors, or capacitors are formed inside the module board 10. A conductive material such as copper (Cu), silver (Ag), gold (Au), or a compound of these metals is used as the conductor pattern 80. If necessary, the conductor patterns 80 are electrically connected to each other with vias (not illustrated) interposed therebetween. The conductor patterns 80 are electrically connected to the electronic components 40 mounted on the module board 10 with vias (not illustrated) interposed therebetween.
Electrode terminals (not illustrated) are formed on a front surface (first surface) 12 and a back surface (second surface) 14 of the module board 10, and the electronic components 40 are mounted on the electrode terminals by using solder bumps 42. The electronic component 40 is, for example, a semiconductor element, a ceramic laminated chip component, a resistor component, a transformer, or the like. These electronic components 40 are mounted, and thus, the module 100 can function as, for example, a high frequency module such as a Bluetooth (registered trademark) module, a wireless LAN module, and an antenna module.
The electronic components 40 mounted on both the surfaces of the module board 10 are covered with the mold portions 20 and 22 which are formed by filling resin, respectively. The electronic components 40 mounted on the front surface 12 of the module board 10 are covered with the mold portion 20 (first mold portion), and the electronic components 40 mounted on the back surface 14 are covered with the mold portion 22 (second mold portion). For example, an epoxy resin containing a silica filler can be used as the molding resin.
A plurality of electrode terminals 70 is formed on a surface 23 of the mold portion 22 opposite to a surface on the module board 10 side. The module 100 is mounted on a mounting board (not illustrated) by the electrode terminals 70. The electrode terminals 70 are electrically connected to the module board 10 through columnar conductors 60 formed by using a conductive member such as copper. A power or signals are transmitted to the electronic components 40 mounted on the module board 10 with the columnar conductors 60 interposed therebetween. The electronic components 40 mounted on the module board 10 are connected to a ground potential of the mounting board with the columnar conductors 60 interposed therebetween. The columnar conductors 60 may be formed by using protruding electrodes, metal pins, plating, or the like. Alternatively, the columnar conductors may be connected by using the solder bumps.
An upper surface 21 and side surfaces 24 of the mold portion 20 (surfaces of the mold portion 20 that connect the upper surface 21 of the mold portion 20 and a surface on the module board 10 side) are covered with the shield 30 (first shield) formed by using a conductive material. Side surfaces 25 of the mold portion 22 (surfaces of the mold portion 22 that connect the lower surface 23 of the mold portion 22 and a surface on the module board 10 side) are covered with the shield 32 (second shield) also formed by using a conductive material. Although not illustrated in
In the module 100 according to the first embodiment, protrusions 15 protruding from the side surfaces of the module board 10 in an X-axis direction of
The shields 30 and 32 prevent electromagnetic waves radiated from the electronic components 40 mounted on the module board 10 from leaking to the outside of the module 100, and prevent the electromagnetic waves from the outside of the module 100 from reaching the outside of the module. That is, EMI can be suppressed by forming the shields 30 and 32 around the module.
As a configuration of the shield for preventing EMI on the board on which the electronic components are mounted on both the surfaces, it is considered that the whole board is covered with one common shield as disclosed in U.S. Pat. No. 9,935,083 (Patent Document 1). However, in such a configuration, although it is possible to suppress the radiation and reaching of the electromagnetic waves to the outside of the module, there is a possibility that the electromagnetic waves radiated from the electronic components formed on one surface (front surface) of the board pass through the shield, propagate to the other surface (back surface), and influence the electronic components on the back surface side.
On the other hand, in the module 100 of the first embodiment, as described above, the shield 30 formed on the front surface 12 side of the module board 10 and the shield 32 formed on the back surface 14 side of the module board 10 are separated by the protrusions 15 formed on the module board 10. With such a configuration, since the electromagnetic waves radiated from the electronic components 40 mounted on one surface (for example, the front surface 12) of the module board can be prevented from propagating to the shield 32 on the back surface 14 side through the shield 30, it is possible to suppress the influence of the electromagnetic waves radiated from the electronic components 40 mounted on one surface of the module board 10 on the electronic components mounted on the other surface. At this time, the shield 30 and the shield 32 are physically separated by the protrusions 15, and thus, the insulation between the two shields can be more reliably secured than when these two shields are separated without using the protrusions 15. Thus, it is possible to more reliably suppress the influence of the electromagnetic waves radiated from the electronic components on the electronic components mounted on both the surfaces of the module board 10.
When the shield 30 and the shield 32 are to be separated without using the protrusions 15, there is a concern that the shield 30 and the shield 32 are electrically connected and short-circuited depending on a distance between an end of the shield 30 and an end of the shield 32. However, the shield 30 and the shield 32 are physically separated by the protrusions 15 as in the first embodiment, and thus, the two shields 30 and 32 can be prevented from being electrically connected on an outer circumference of the module 100.
(Variation of Shield Shape)
In the module 100 in
Hereinafter, a modification example of the shield shape formed on the side surfaces of the module board 10 will be described with reference to
In an example of a module 100A illustrated in
The electromagnetic waves generated in the electronic components 40 mounted on the front surface 12 side of the module board 10 pass through the mold portion 20 and are radiated. Thus, the shield 30 is formed so as to cover at least the mold portion 20, and thus, the radiation of the electromagnetic waves from the electronic component 40 to the outside of the module 100A is suppressed.
Since a part of the electromagnetic waves generated in the electronic components 40 can be radiated even though the electromagnetic waves pass through the module board 10, the configuration of the module 100 of
When at least a part of the side surface of the module board 10 is covered with the shield 30 or the shield 32 as in the module 100 and the module 100A, the shielding effect can be obtained also for the conductor pattern among the conductor patterns 80 formed inside the module board 10 overlapping the shields 30 and 32 when the side surface of the module board 10 is viewed in plan view from a side on which the protrusion 15 is present. That is, it is possible to prevent electromagnetic wave interference from the outside from reaching the conductor patterns 80 inside the module board 10 indirectly covered with the shields 30 and 32.
In a module 100C illustrated in
In the case of such a configuration, it is more preferable that a thickness of the shield formed on the protrusion 15, that is, the shield covering at least one of the surfaces of the protrusion 15 in contact with the side surfaces of the module board 10 (dimension in a Z-axis direction) is more than a thickness of the shield formed on the side surface portion of the module board 10 (dimension in the X-axis direction). As will be described later, in a manufacturing process of the module, when chips of adjacent modules are separated, the portion of the protrusion 15 is cut by a dicing saw. At this time, when the rigidity of the shield formed on the protrusion 15 is weak, there is a concern that the protrusion 15 and the shield are peeled off or the protrusion 15 itself may be broken when the module is separated. Thus, the rigidity of the shield and the protrusion 15 itself is improved by setting the thickness of the shield formed on the protrusion 15 to be more than the thickness of the shield on the side surface of the module board 10. Accordingly, in a step of individually separating the modules, it is possible to prevent the shield from being peeled off from the protrusion 15 and/or the protrusion 15 from being broken.
In a module 100D in a modification example of
In general, the shield 31 and the shield 32 are often formed by using a sputtering method. When the sputtering method is used, it is difficult for a shield film to be formed on a portion at which a corner is formed. Specifically, when the corner is formed at the portion of the protrusion 15 in contact with the side surface of the module board 10 as in the modules 100A to 100C, it is difficult for the shield film to be formed to the contact portion, and it is conceivable that the shield 30 and the shield 32 are interrupted between the side surface of the module board 10 and the protrusion 15.
On the other hand, according to the configuration of the module 100D illustrated in
Even though the shape of the protrusion 15A is as illustrated in
(Method of Grounding Shield)
The shields 30 and 32 are generally connected to the ground potential in order to prevent the electromagnetic waves captured by the shields 30 and 32 from being re-radiated from the shields 30 and 32. As described with reference to
More specifically, in a step of forming the module board 10, the ground electrodes GND are formed in layers different from a layer on which the protrusion 15 is formed, and are formed such that the ends thereof are at positions protruding in the directions of the protrusions 15 from the positions of the side surfaces of the module board 10. Accordingly, the ground electrodes GND are exposed on the side surfaces of the module board 10 by performing half-cutting by using a dicer. Thereafter, the shields 30 and 32 are formed so as to cover at least a part of the side surfaces of the module board 10, and thus, the ground electrodes GND formed inside the module board 10 and the shields 30 and 32 are electrically connected.
In
According to the configuration of the module 100F, the peeling of the shield 30 and the shield 32 on the side surface of the module board 10 can be suppressed. As with the shield 30 and the shield 32, the ground electrode GND formed by using a conductive material has higher adhesion to the shield 30 and the shield 32 than the protrusion 15 formed by using an insulating material. For example, in the module 100E in which the shield 30 and the shield 32 reach the root portion of the protrusion 15 and the ground electrodes GND are separated from the root portion of the protrusion 15, there is a concern that the shield 30 and the shield 32 are peeled off with the root portion of the protrusion 15 as a start point. On the other hand, in the module 100F, since the ground electrodes GND having high adhesion to the shield 30 and the shield 32 are disposed at the root portion of the protrusion 15, such peeling can be easily suppressed.
In the configuration in which the shields are also formed on the upper surface side and the lower surface side of the protrusion 15 described in
In a step of performing the half-cutting by using the dicer, the shields 30 and 32 are formed after the module board 10 is cut until the via 82 is exposed. Accordingly, the shields 30 and 32 are connected to the ground electrode GND with the via 82 interposed therebetween.
According to the configuration of the module 100G, the connectivity between the ground electrode GND inside the module board 10 and the shield 30 is improved.
For example, in the configuration of the modules 100E and 100F in which the ground electrodes GND are connected to the shield 30 and the shield 32 on the side surfaces of the module board 10, the ground electrodes GND are formed so as to be exposed on the side surfaces of the module board 10 by the half-cutting step by using the dicer as will be described later in the description of manufacturing process of
On the other hand, in the configuration of the module 100G in which the ground electrode GND and the shield are connected in the portion of the protrusion 15 with the via 82 interposed therebetween, the via 82 is formed by the half-cutting step by using the dicer so as to be exposed on the upper surface side of the protrusion 15. At this time, in the via 82, a surface exposed on the upper surface side of the protrusion 15 comes into contact with a bottom surface of the blade of the dicing saw. Since the machinability of the bottom surface of the blade is less likely to deteriorate even though the bottom surface wears compared to the side surface of the blade, the via 82 connected to the ground electrode GND is easily exposed to the upper surface side of the protrusion 15. Accordingly, the connectivity between the ground electrode GND and the shield 30 or the shield 32 can be improved as compared with the configuration of the module 100E or the like.
(Dimension of Protrusion)
The module 100 has a substantially rectangular shape including a first side S1 and a second side S2 adjacent to the first side S1 when viewed in plan view. In
It is preferable that a thickness of the protrusion 15 in a stacking direction (Z-axis direction in
[Manufacturing Process of Electronic Component Module]
Next, the manufacturing process of the electronic component module described above will be described. In the following description, the case of the module 100C in which the side surfaces of the module board 10 and the upper surface side and the lower surface side of the protrusion 15 are covered with the shields 30 and 32 as described with reference to
With reference to
Subsequently, in S20, the electronic components 40 are mounted on both the surfaces of the module board 10. Specifically, the solder bumps are formed by printing on the electrode terminals formed on the front and back surfaces of the module board 10. The electronic components 40 and the electrode terminals are coupled by mounting the electronic components 40 on the formed solder bumps and then heating and melting the solders in a reflow step. If necessary, the board may be washed after the reflow.
In a mounting step of the electronic component 40, the front surface 12 and the back surface 14 of the module board 10 may be simultaneously mounted, or the mounting of the electronic components on the other surface may be executed after the mounting of the electronic components on one surface is completed.
When the mounting of the electronic components 40 on both the surfaces of the module board 10 is completed, both the surfaces of the module board 10 are molded with resin in S30. As described above, the epoxy resin containing the silica filler can be used as the molding resin.
Alternatively, alumina may be used as the filler in order to enhance heat conduction.
For example, a known method such as a compression mold, a transfer mold, a liquid resin mold, or a sheet resin mold can be used as the molding method.
In a molding step, the front and back surfaces of the module board 10 may be molded all at once, or may be molded one by one. If necessary, the module board 10 may be plasma-washed before the molding step.
After the molding step, the mold portion 22 on the back surface side of the module is ground by using a grinder to expose the columnar conductor 60 from the mold portion 22 such that I/O terminal portions for mounting the module on another board can be formed.
Thereafter, in S40, the chips of the adjacent modules are half cut by using the dicer, a laser cutter, or the like. The half-cutting is a step of forming cuts from the front surface side and the back surface side of the module board 10 to the middle of the module board 10. The portion remaining without being cut by this half-cutting becomes the protrusion 15. When the thickness of the protrusion 15 increases, since the rigidity of the protrusion 15 increases, the protrusion 15 can be prevented from being broken during the handling of the board in the manufacturing process. On the other hand, when the thickness of the protrusion 15 is reduced, since an area covered with the shields on the side surfaces of the module board 10 increases, the shielding effect of the whole module can be improved.
When the half-cutting is performed by using the dicing saw, for example, a dicing saw having a blade width of 0.1 mm or more and less than 1.0 mm can be used. When the shields are formed by sputtering in the subsequent process, as the blade width becomes wider, the sputtering adhesion is improved. On the other hand, when a dicing saw having a narrower blade width is used, since the amount of cutting can be reduced, the number of modules manufactured from one board can be increased, and thus, the yield can be increased.
In the half-cutting, a depth of the cut from the front surface side and a depth of the cut from the back surface side of the module board 10 may be equal or different.
When the half-cutting step is completed, the shield films are formed on the front and back surfaces of the module by sputtering in S50. The shield films may be formed as a plurality of sputtered films, and can be formed as, for example, three layers of an adhesion layer, a conductive layer, and a corrosion resistant layer.
A thickness of the shield film can be, for example, 2 μm or more and less than 5 μm. It is preferable that the portions where the protrusions 15 are formed are formed to be thicker than the shield films formed on the side surfaces of the module board 10. In a division step into the modules to be described later, since the protrusions 15 are fully cut, the rigidity is increased by setting the shield films of the portions of the protrusions 15 to be thicker, the shield films are less likely to be peeled off from the protrusions 15 at the time of full-cut. The full-cut is a step of cutting from the upper surface side to the lower surface side of the protrusions 15 such that there is no uncut portion.
Subsequently, in order to form the I/O terminal portions for mounting the module on another board, the shield films are removed by grinding the back surface side of the module by using the grinder in S60 to expose the mold portion 22 and the columnar conductor 60 on the back surface side of the module board 10.
The electrode terminals 70 are electrically connected to the columnar conductors 60 on the back surface side of the mold portion 22, and thus, the I/O terminal portions (input and output terminal portions) are formed (S70).
In S80, the portions where the protrusions 15 are formed by the half-cutting are fully cut by using the dicer or the laser, and thus, the adjacent chips are separated. Accordingly, the electronic component module is completed.
Referring to
When the module board 10 is formed, the electronic components 40 are mounted on the front surface 12 and the back surface 14 of the module board 10 as illustrated in
Subsequently, referring to
Thereafter, as illustrated in
As illustrated in
Subsequently, when the shield films are formed, the shield 32 on the lower surface side of the module is ground by the grinder as illustrated in
Finally, the portions of the protrusions 15 are fully cut, and the chips of the adjacent modules are separated from each other (S80 in
By manufacturing the electronic component module according to the manufacturing process described above, in the electronic component module in which the electronic components are mounted on both the surfaces of the module board, the shield covering the upper surface of the module and the shield covering the lower surface are separated by the protrusions protruding from the side surfaces of the module board. Accordingly, the electromagnetic waves generated in the electronic components mounted on one surface of the module board can be prevented from being transmitted to the electronic components mounted on the other surface through the shields. Accordingly, it is possible to effectively suppress EMI by such a shield structure.
The configuration in which the electronic components are mounted on both the front surface and the back surface of the module board has been described in the electronic component module of the first embodiment.
In a second embodiment, an example of a configuration in which an antenna circuit is disposed on the front surface of the module board and the electronic components are mounted on the back surface will be described.
Referring to
In the electronic component module 100H, the transmission of the electromagnetic waves generated in the antenna circuits 200 to the electronic components 40 mounted on the back surface 14 through the shields 30 and 32 can be suppressed by the protrusions 15 formed on the side surfaces of the module board 10. Accordingly, it is possible to effectively suppress EMI.
The electronic components 40 may be mounted on the front surface 12 of the module board 10 in addition to the antenna circuits 200, as in an electronic component module 100I of a modification example illustrated in
In each of the electronic component modules illustrated in the first embodiment and the second embodiment, the configuration in which the module board is connected to the external mounting board by using the electrode terminals 70 disposed on the back surface side has been described. In a third embodiment, a configuration in which a connector is used for connection with the mounting board will be described.
Referring to
As stated above, in the configuration in which the connector is disposed as a connection terminal with the external board, the transmission of the electromagnetic waves generated in the antenna circuits 200 to the electronic components mounted on the back surface side through the shields can also be suppressed by the protrusions 150 formed on the side surfaces of the module board 10, and thus, EMI can be effectively suppressed.
As with
The description of the currently disclosed embodiments is illustrative in all respects, and should not be considered as limiting. The scope of the present disclosure is illustrated by the claims rather than the description of the embodiments described above, and is intended to include all modifications within the meaning and scope equivalent to the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| JP2018-184682 | Sep 2018 | JP | national |
This is a continuation of International Application No. PCT/JP2019/038252 filed on Sep. 27, 2019 which claims priority from Japanese Patent Application No. 2018-184682 filed on Sep. 28, 2018. The contents of these applications are incorporated herein by reference in their entireties.
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| Entry |
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| Number | Date | Country | |
|---|---|---|---|
| 20210204395 A1 | Jul 2021 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2019/038252 | Sep 2019 | US |
| Child | 17198489 | US |
