JP2004179434A - Electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small electronic device whose production cost can be suppressed to be low. <P>SOLUTION: A plurality of electronic components 2 are placed on a center region of an upper face of a rectangular circuit board 1, and second electronic components 3 higher than the first electronic components 2 are placed at peripheral regions. A flat protection member 4 whose outer dimension is smaller than the circuit board 1 and whose upper face is positioned on a level equal to the second electronic parts 3 or below them is installed in a centroid position of the circuit board 1 where the first electronic components 2 and the second electronic components 3 are placed at upper faces of the first electronic components 2. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electronic device used for various communication devices, electronic devices, and the like.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, electronic devices have been used for communication devices, electronic devices, and the like.
As such a conventional electronic device, for example, as shown in FIG. 3, a plurality of electronic components 32 are mounted on an upper surface of a circuit board 31, and a protective member 3 is attached to the upper surface of the electronic components 32. A structure is known (for example, see Patent Document 1).
[0003]
In the electronic device 30 having such a structure, the protection member 32 can be mounted on the circuit board 31 without directly joining the protection member 32 to the circuit board 31, and the height of the electronic component 32 and the protection member 32 can be increased. And the height of the entire structure can be reduced.
[0004]
[Patent Document 1]
JP-A-9-97990 (FIG. 1)
[0005]
[Problems to be solved by the invention]
By the way, according to the above-described conventional electronic device, when the protection member 32 is bonded to the upper surface of the electronic component 32, the protection member 32 is displaced with respect to the circuit board 31, or the plurality of electronic components 32 If the electronic device is mounted in an uneven distribution state on the upper surface of the electronic device 31, the weight balance of the entire electronic device will be deteriorated. When such an electronic device is mounted on a motherboard or the like by using a vacuum suction device, the electronic device may drop from the suction head due to the above-described bias in weight. In particular, the smaller the electronic device, the smaller the suction area and the weaker the suction power of the suction head, and thus the more difficult it is to hold and hold the electronic device with the suction head. However, there was a drawback that it became worse.
[0006]
In addition, the circuit board 31 of the above-described conventional electronic device is usually formed of a ceramic material, and has a significantly different coefficient of linear expansion from the protective member 32 formed of a metal material or the like. When heat from the outside is applied during use or the like, there is also a disadvantage that the electronic device is deformed by thermal stress generated between the circuit board 31 and the protection member 32.
[0007]
SUMMARY An advantage of some aspects of the invention is to provide an electronic device that is low in height and small in size, and that can improve workability when mounted on a motherboard or the like. .
[0008]
[Means for Solving the Problems]
In the electronic device of the present invention, on a top surface of a rectangular circuit board, a plurality of first electronic components are placed in a central region and a second electronic component that is taller than the first electronic component is placed in a peripheral region. At the same time, on the upper surface of the first electronic component, the outer dimension is smaller than that of the circuit board at the center of gravity of the circuit board on which the first electronic component and the second electronic component are mounted. (2) A flat plate-like protective member located at the same level as or below the electronic component is attached.
[0009]
The electronic device according to the present invention is characterized in that the second electronic component is arranged near four corners on the upper surface of the circuit board.
[0010]
Further, in the electronic device according to the present invention, the total weight of the second electronic component occupies 2% to 15% of the total weight of the entire electronic device.
[0011]
Still further, in the electronic device according to the present invention, the flat plate-shaped protective member is made of metal.
[0012]
Furthermore, the electronic device of the present invention is characterized in that the flat protective member is attached to the first electronic component via a bonding material having a Young's modulus of 0.0001 Pa to 0.01 Pa. is there.
[0013]
According to the electronic device of the present invention, the plurality of first electronic components are placed in the central region of the upper surface of the circuit board, and the second electronic component that is taller than the first electronic component is placed in the peripheral region. Therefore, the weight balance of the entire electronic device is improved, and the flat protection member attached to the upper surface of the first electronic component has a smaller outer dimension than the circuit board, and the attachment position of the protection member is temporarily shifted. However, since the range is limited to a narrow range surrounded by the second electronic component, the influence on the overall weight balance is relatively small. Accordingly, workability when mounting the electronic device on a motherboard or the like using the vacuum suction device can be improved.
[0014]
Moreover, according to the electronic device of the present invention, the height of the upper surface of the flat plate protective member is equal to or lower than the upper surface of the second electronic component, and the height of the upper surface of the protective member is lower than the upper surface of the second electronic component. Since the height is not higher than the upper surface of the second electronic component, it is possible to further reduce the size and height of the electronic device.
[0015]
Further, according to the electronic device of the present invention, by disposing the second electronic component in the vicinity of the four corners of the upper surface of the circuit board, the bonding balance between the protection member and the first electronic component becomes extremely good. When the electronic device is mounted on a motherboard or the like using a vacuum suction device, it is possible to effectively prevent the occurrence of poor suction or the like.
[0016]
Further, according to the electronic device of the present invention, since the protection member reduces the penetration of electromagnetic waves by forming the plate-shaped protection member from metal, it is possible to obtain an electronic device with less variation in characteristics with respect to electromagnetic noise. become.
[0017]
Furthermore, according to the electronic device of the present invention, assembling the electronic device by attaching the flat protective member to the first electronic component via a bonding material having a Young's modulus of 0.0001 Pa to 0.01 Pa. In the process, even if the linear expansion coefficients of the circuit board and the protection member are different, the thermal stress generated between the circuit board and the protection member is buffered (dispersed), so that the deformation of the electronic device is minimized. Can be.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is an external perspective view of an electronic device according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the electronic device of FIG. 1. The electronic device shown in FIG. The electronic component 2 has a structure in which a first electronic component 2 and a second electronic component 3 are mounted, and a protection member 4 is attached to an upper surface of the electronic component 2.
[0019]
The rectangular circuit board 1 is formed by stacking a plurality of dielectric layers made of a glass-ceramic material or the like that can be fired at a relatively low temperature of, for example, 800 ° C. to 1200 ° C. The conductors provided in the layers form circuit wirings and connection pads, respectively.
Examples of the ceramic component of the glass-ceramic material forming the rectangular circuit board 1 include insulating ceramic materials such as cristobalite, quartz, corundum (α-alumina), mullite, cordierite, MgTiO ₃ , and CaTiO _3. , BaTiO _3, a dielectric ceramic material such as TiO _2, Ni-Zn ferrite, magnetic ceramic material such as Mn-Zn ferrite is used, for example, an average particle diameter of 0.5 to 6.0 m, preferably 0. What is ground to 5 to 2.0 μm is used. Note that two or more ceramic materials may be used in combination.
On the other hand, as the glass component of the glass-ceramic material, a crystal phase of cordierite, mullite, anorthite, serdian, spinel, garnite, willemite, dolomite, petalite or a substituted derivative thereof or a crystal phase having a spinel structure is precipitated by firing. well with whatever glass long as, for _{example, B 2 O 3, SiO 2} , Al 2 O 3, ZnO, glass frit containing an alkaline earth oxide. These glass frit have a wide vitrification range, and a sag point is set at, for example, 600 to 800 ° C.
[0020]
The thickness of each dielectric layer forming the rectangular circuit board 1 is set, for example, to 20 μm to 300 μm.
[0021]
The conductor provided on the surface or inside of the circuit board 1 may be a circuit wiring interposed between dielectric layers, a via-hole conductor buried inside the dielectric layer, or an electronic component or the like on the surface of the circuit board 1. The conductor is constituted by connection pads and the like, and the material of the conductor is selected in consideration of compatibility with the dielectric material forming the dielectric layer. Such a conductor is formed of a conductive material mainly containing an Ag alloy such as Ag, Ag-Pd, Ag-Pt, or a Cu-based, W-based, Mo-based, or Pd-based conductive material. It is set to 5 to 25 μm. The diameter of the via hole conductor is appropriately set according to the thickness of the dielectric layer and the like. When the thickness of the dielectric layer in which the via hole conductor is embedded is 20 μm to 300 μm, the diameter of the via hole conductor is, for example, 50 μm. ３００300 μm.
[0022]
The circuit board 1 has most of the circuit wiring embedded therein, and only connection pads for electrically connecting terminals of the electronic components 2 and 3 are provided on the main surface of the circuit board 1. I have. By adopting such a configuration, the degree of freedom of design is greatly increased, and the electronic components 2 and 3 can be mounted on the circuit board 1 with high density.
[0023]
Note that a conventionally known ceramic green sheet laminating method or the like is used for manufacturing such a circuit board 1. Specifically, first, a ceramic green sheet is obtained by adding and mixing an appropriate organic solvent or the like to the above-mentioned ceramic raw material powder to form a slurry, and employing a conventionally known doctor blade method or the like. Next, the obtained ceramic green sheet is coated and filled with a conductor interposed between the dielectric layers and a via hole conductor buried inside the dielectric layer by conventionally known screen printing or the like. Are sequentially laminated and press-molded to obtain a laminate of ceramic green sheets. Finally, the circuit board 1 is manufactured by firing the obtained laminate at a high temperature.
[0024]
On the other hand, the first electronic component 2 and the second electronic component 3 mounted on the upper surface of the circuit board 1 are surface-mounted electronic components, and are connected to connection pads on the upper surface of the circuit board via an adhesive such as solder. And are electrically connected. As the first electronic component 2, for example, a small electronic component such as a diode, a chip capacitor, or a chip resistor is used. As the second electronic component 3, for example, a first electronic component such as a chip inductor or an IC package is used. A relatively large electronic component that is taller than 2 is used.
[0025]
In the step of mounting the first electronic component 2 and the second electronic component 3 on the circuit board 1, first, a solder paste obtained by mixing a powdery solder and a vehicle is applied onto the connection pads on the circuit board 1. The first electronic component 2 and the second electronic component 3 are mounted in a predetermined arrangement. Then, the solder is melted and solidified by the reflow, whereby the first electronic component 2 and the second electronic component 3 are electrically connected to the connection pads of the circuit board 1 via the solder.
[0026]
The protective member 4 attached to the upper surfaces of the plurality of first electronic components 2 is made of a metal material such as iron or Kovar which is relatively close to the coefficient of linear expansion of the circuit board 1 and has a flat shape. Is formed. The flat protective member 4 is for physically protecting the first electronic component 2. When the electronic device 10 is mounted on a motherboard or the like, the upper surface of the protective member 4 is provided with a vacuum suction device. The suction head is contacted, and the electronic device 10 is vacuum-sucked at this portion.
[0027]
An important point of the electronic device according to the present embodiment is that a plurality of first electronic components 2 are provided in a central region of the upper surface of the circuit board 1 and a second electronic component which is taller than the first electronic components 2 is provided in a peripheral region. 3 is placed, whereby the weight balance of the entire electronic device is improved. Further, in this case, the flat protection member 4 attached to the upper surface of the first electronic component 2 has a smaller outer dimension than the circuit board 1, and even if the attachment position of the protection member 4 is shifted, the range is the third. Since it is limited to a narrow range surrounded by two electronic components, the influence on the overall weight balance is relatively small. Therefore, workability when mounting the electronic device 10 on a motherboard or the like using a vacuum suction device is improved.
[0028]
Moreover, according to the electronic device of the present embodiment described above, the height of the upper surface of the flat plate protection member 4 is equal to or lower than the upper surface of the second electronic component 3. Since the height of the upper surface of the protection member 4 is not higher than the upper surface of the second electronic component 3, the size and height of the electronic device 10 can be further reduced.
[0029]
Further, according to the electronic device of the present embodiment, since the second electronic component 3 is disposed near the four corners on the upper surface of the circuit board, the bonding balance between the protection member 4 and the first electronic component 2 is extremely good, When the electronic device 10 is mounted on a motherboard or the like using a vacuum suction device, the suction state of the suction head with respect to the electronic device 10 can be stabilized, and the occurrence of poor suction or the like can be effectively prevented.
[0030]
Further, according to the electronic device of the present embodiment, since the flat protection member 4 is formed of metal, the protection member 4 reduces the penetration of electromagnetic waves, and the electronic device 10 has a small variation in characteristics with respect to electromagnetic noise. Can be obtained.
Since the flat protection member 4 is made of metal, the penetration of the electromagnetic wave is reduced by the protection member 4, so that it is possible to obtain the electronic device 10 in which the characteristic changes little with respect to the electromagnetic wave noise.
[0031]
Furthermore, according to the electronic device of the present embodiment, since the flat protective member 4 is attached to the first electronic component 2 via a bonding material having a Young's modulus of 0.0001 Pa to 0.01 Pa, Even if the linear expansion coefficients of the circuit board 1 and the protection member 4 are different, the thermal stress generated between the circuit board 1 and the protection member 4 is favorably buffered (dispersed), and the electronic device 10 is deformed. Can be suppressed as small as possible.
[0032]
Thus, in the electronic device of the present invention, on the upper surface of the rectangular circuit board 1, a plurality of the first electronic components 2 are provided in the central region, and the second electronic devices 2 are taller than the first electronic components 2 in the peripheral region. The component 3 is placed, and the outer dimension of the circuit board 1 on the upper surface of the first electronic component 2 is smaller than the center of gravity of the circuit board 1 on which the first electronic component 2 and the second electronic component 3 are placed. By attaching the flat protective member 4 which is small and whose upper surface is equal to or lower than the second electronic component 3, it functions as an electronic device used in various high-frequency electronic devices.
[0033]
Note that the present invention is not limited to the above-described embodiment, and various changes, improvements, and the like can be made without departing from the gist of the present invention.
[0034]
For example, in the above-described embodiment, the circuit board 1 is formed of a glass-ceramic material. Alternatively, the circuit board 1 may be formed of another ceramic material such as alumina ceramics or an organic material such as glass-epoxy resin. May be formed.
[0035]
Further, in the above-described embodiment, the protection member 4 is formed of a metal material. However, for example, in an environment where there is no influence of electromagnetic wave noise, the protection member 4 may be formed of an organic material. . On the other hand, in an environment where the influence of electromagnetic wave noise is large, it is preferable that the protective member 4 is configured to be grounded via the circuit board 1 or the like.
[0036]
Furthermore, in the above-described embodiment, the first electronic component 2 is first mounted on the circuit board 1, and then the protection member 4 is adhered to the first electronic component 2. The mounting of the first electronic component 2 and the second electronic component 3 on the substrate 1 and the bonding of the protective member 4 to the upper surface of the first electronic component 2 may be performed simultaneously by one reflow. In this case, There is also an advantage that the number of steps for manufacturing an electronic device can be reduced.
[0037]
Furthermore, in the above-described embodiment, most of the circuit wiring is buried inside the circuit board 1, and connection pads to which the terminals of the electronic components 2 and 3 are electrically connected are provided on the main surface of the circuit board 1. Although only the circuit wiring is provided, a circuit wiring other than the connection pad may be partially arranged on one main surface of the circuit board 1 instead.
[0038]
Furthermore, in the above-described embodiment, a product name, a serial number, or the like is marked on the upper surface (outer surface) of the protective member 4 to display the product name, the serial number, or the like. When attaching to the electronic component 2, it goes without saying that the second electronic component 3 may be used as a marker for position recognition.
[0039]
【The invention's effect】
According to the electronic device of the present invention, the plurality of first electronic components are placed in the central region of the upper surface of the circuit board, and the second electronic component that is taller than the first electronic component is placed in the peripheral region. Therefore, the weight balance of the entire electronic device is improved, and the flat protection member attached to the upper surface of the first electronic component has a smaller outer dimension than the circuit board, and the attachment position of the protection member is temporarily shifted. However, since the range is limited to a narrow range surrounded by the second electronic component, the influence on the overall weight balance is relatively small. Therefore, workability when mounting the electronic device on a motherboard or the like using the vacuum suction device can be improved.
[0040]
Moreover, according to the electronic device of the present invention, the height of the upper surface of the flat plate protective member is equal to or lower than the upper surface of the second electronic component, and the height of the upper surface of the protective member is lower than the upper surface of the second electronic component. Since the height is not higher than the upper surface of the second electronic component, it is possible to further reduce the size and height of the electronic device.
[0041]
Further, according to the electronic device of the present invention, by disposing the second electronic component in the vicinity of the four corners of the upper surface of the circuit board, the bonding balance between the protection member and the first electronic component becomes extremely good. When the electronic device is mounted on a motherboard or the like using a vacuum suction device, it is possible to effectively prevent the occurrence of poor suction or the like.
[0042]
Further, according to the electronic device of the present invention, since the protection member reduces the penetration of electromagnetic waves by forming the plate-shaped protection member from metal, it is possible to obtain an electronic device with less variation in characteristics with respect to electromagnetic noise. become.
[0043]
Still further, according to the electronic device of the present invention, the flat protective member is attached to the first electronic component via a bonding material having a Young's modulus of 0.0001 Pa to 0.01 Pa to protect the circuit board from the first electronic component. Even if the members have different coefficients of linear expansion, the thermal stress generated between the circuit board and the protective member is favorably buffered (dispersed), so that the deformation of the electronic device can be minimized.
[Brief description of the drawings]
FIG. 1 is an external perspective view of an electronic device according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of the electronic device of FIG.
FIG. 3 is a cross-sectional view of a conventional electronic device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Circuit board 2 ... 1st electronic component 3 ... 2nd electronic component 4 ... Protective member 10 ... Electronic device

Claims (5)

On a top surface of a rectangular circuit board, a plurality of first electronic components are placed in a central region, and a second electronic component that is taller than the first electronic components is placed in a peripheral region. On the upper surface of the component, the outer dimension is smaller than the circuit board, and the height of the upper surface is equal to or lower than the second electronic component, at the center of gravity of the circuit board on which the first electronic component and the second electronic component are mounted. An electronic device comprising a plate-like protection member mounted on the electronic device. The electronic device according to claim 1, wherein the second electronic component is arranged near four corners on an upper surface of the circuit board. 3. The electronic device according to claim 1, wherein a total weight of the second electronic component occupies 2% to 15% of a total weight of the entire electronic device. 4. 4. The electronic device according to claim 1, wherein the flat protection member is made of metal. 5. The flat protection member is attached to the first electronic component via a bonding material having a Young's modulus of 0.0001 Pa to 0.01 Pa. 6. Electronic devices.

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