JP5144210B2 - Semiconductor device - Google Patents

Description

  The present invention relates to a semiconductor device, and more particularly to a semiconductor device characterized by a structure for increasing the mounting density and reducing the size of a semiconductor device mounted on a small electronic device such as a mobile phone.

  As electronic devices have become smaller and higher performance in recent years, it has been required to miniaturize electronic components including semiconductor elements and circuit boards on which they are mounted, and to increase the mounting density. Yes.

Generally, in an electronic device, a technique for mounting an electronic component such as a semiconductor element on a rigid circuit board surface is used.
Thus, when mounting electronic components on a rigid circuit board, mounting density can be expected by mounting electronic components on both sides of the circuit board. The mounting stress of the electronic components mounted on the board also increased, and there was a problem that the mounting reliability was lowered.

In addition, attempts have been made to improve the three-dimensional mounting density by mounting electronic components on a flexible circuit board and then folding them.
However, in a mounting structure in which a flexible circuit board is folded, the load on the electronic component mounting section increases due to insufficient rigidity of the circuit board, so that mounting reliability is reduced and it is difficult to dissipate heat generated from the semiconductor element. There is a problem.

Therefore, it has been proposed to mount electronic components on the surface of a plurality of rigid circuit boards having a small area, connect the plurality of rigid circuit boards having a small area with a flexible board, and fold it at the flexible board portion. (For example, refer to Patent Document 1).
JP 2001-358422 A

  However, when a rigid flexible board having a rigid structure in the electronic component mounting portion is required, a certain thickness is required to ensure the hardness of the board, and the board thickness of the entire semiconductor device increases. There is a problem that the mounting density is lowered.

  Accordingly, an object of the present invention is to enable downsizing and high-density mounting of an apparatus when an electronic component including a semiconductor element is mounted on a circuit board.

Now, with reference to FIG. 1, means for solving the problems in the present invention will be described.
In order to solve the above problems, the present invention provides a circuit board 1 having flexibility, a plurality of electronic components 2 mounted on one surface of the circuit board 1, and a circuit board 1 in a semiconductor device. The metal plate 3 having a thickness of 50 μm to 300 μm fixed to the other surface of the metal plate 3 is provided with cut-out portions on both side surfaces in the longitudinal direction of the metal plate 3, and the circuit board 1 and the metal plate 3 is bent at bent portions provided on the circuit board 1 and the metal plate 3 so that the electronic components 2 face each other.

Thus, by fixing the metal plate 3 having a thickness of 50 μm to 300 μm to the other surface of the flexible circuit board 1, the load on the electronic component mounting portion due to insufficient rigidity of the flexible circuit board 1 is greatly increased. In addition, since the metal plate 3 is thinner than the rigid circuit board 1, it is possible to increase the mounting density. As a result, electronic devices such as mobile phones can be made smaller and thinner. It becomes possible. If the thickness of the metal plate 3 is less than 50 μm, sufficient rigidity cannot be obtained, while if it exceeds 300 μm, bending of the metal plate 3 becomes difficult. In particular, since the cut-off portions are provided on both side surfaces of the metal plate 3 in the longitudinal direction, the side surface of the flexible circuit board 1 can be protected and the positions of the circuit board 1 and the metal plate 3 can be protected. Deviation can be prevented.

As the metal plate 3 in this case, any of stainless steel, phosphor bronze, 4-2 alloy, or aluminum alloy having high rigidity is preferable .

  In this case, it is desirable that the metal plate 3 is electrically connected to the ground electrode, so that a simple electromagnetic shield structure can be realized against external electromagnetic waves.

  In addition, it is desirable to insert a metal plate that functions as at least one of heat dissipation or electromagnetic shielding between the electronic components 2 facing each other, thereby avoiding interference between the electronic components 2 facing each other. The heat dissipation of the electronic component 2 that requires heat dissipation is improved.

  In addition, the electronic component 2 includes at least two opposing portions facing each other, and opposing portions are respectively disposed on both sides of the bending portion, and a common metal plate between the electric components 2 in the two opposing portions. May be inserted and a heat radiating fin may be formed in a part of the common metal plate, thereby enhancing the heat radiating effect.

Further, the metal plate 3 may not be fixed on one end side of the circuit board 1 and a connector terminal may be provided on one end side.
Such a configuration facilitates extraction of the electrode.

  According to the present invention, after mounting an electronic component on the surface of a circuit formed on one side of a metal plate, the mounting area is reduced by folding the metal plate of the portion where the component is not mounted together with the circuit, and at the same time, As a ground electrode, the metal plate is exposed on the surface, and the metal plate is inserted into the inner gap where the parts face each other, and this is joined to the metal plate exposed on the surface, so that high-density mounting and cooling, and even electronics It is possible to simultaneously shield the component from electromagnetic waves.

  In the present invention, for example, stainless steel, phosphor bronze, 4-2 alloy, or the like, on the other surface of the circuit board 1 in which a plurality of electronic components including semiconductor elements are mounted on one surface and at least partially flexible. A metal plate made of any one of aluminum alloys and having a thickness of 50 to 300 μm is fixed, and the circuit board is bent together with the metal plate in at least one place in a direction in which a plurality of mounted electronic components face each other. The outer shell is formed at least partially.

  Further, if necessary, a metal plate constituting the outer shell may be electrically connected to the ground electrode, or a metal that functions as at least one of heat dissipation or electromagnetic shielding in the space of the electronic components facing each other. A board is inserted.

Next, a semiconductor device according to a first embodiment of the present invention will be described with reference to FIGS.
See Figure 2
FIG. 2 is a schematic configuration diagram of the flexible circuit board 11 in a state in which the electronic components 13 _{1 to} 13 ₆ such as semiconductor elements according to the first embodiment of the present invention are mounted, and the thickness is, for example, 0.4 mm. An opening 12 for taking out a connector terminal is formed in a bent portion at the center of the circuit board 11, and a metal ground layer 14 made of SUS is fixed to a surface opposite to the mounting surface of the flexible circuit board 11. ing.

See Figure 3
FIG. 3 is a schematic perspective view of the metal ground layer according to the first embodiment of the present invention, and an opening provided in the flexible circuit board 11 by pressing a SUS plate having a thickness of 50 to 300 μm, for example, 100 μm. 12 is provided with an opening 15 corresponding to 12, and a cut-off portion 16 having a height substantially corresponding to the flexible circuit board 11 is provided on both side surfaces in the longitudinal direction.

See Figure 4
FIG. 4 is a schematic side view of the semiconductor device in a folded state, in which the flexible circuit board 11 is folded with the metal ground layer 14 and the electronic components 13 _{1 to} 13 ₆ at the central bent portion so as to face each other. After folding, the folded shape is held by the rigidity of the metal ground layer 14, and the flexible circuit board 11 is held by the metal ground layer 14 by the cut-off portion 16 (not shown).

As a method of fixing the flexible circuit board 11 to the metal ground layer 14, it may be fixed using a double-sided adhesive tape or an adhesive 17 as shown in the figure.
In this case, as shown in the figure, it is desirable that the flexible circuit board 11 is not fixed to the metal ground layer 14 at the bent portion.
With such a structure, the flexible circuit board 11 can exhibit a bent shape unique to the metal ground layer 14 at the bent portion.

When the ground electrode of the flexible circuit board 11 and the metal ground layer 14 are electrically connected, a double-sided adhesive tape having conductivity or a conductive adhesive is used.
The conductive double-sided pressure-sensitive adhesive tape only needs to have a conductive structure, and in this case, the conductive part is the ground electrode of the flexible circuit board 11. And the metal ground layer 14 in contact with each other.

  In this case, the load on the electronic component mounting portion due to insufficient rigidity of the flexible circuit board 11 can be greatly reduced, and the metal ground layer 14 has a thickness of 50 to 300 μm, so that high-density mounting is not hindered. .

Next, with reference to FIG. 5, the semiconductor device of Example 2 of this invention is demonstrated.
See Figure 5
FIG. 5 is a diagram illustrating the configuration of the semiconductor device according to the second embodiment of the present invention. The thin portion 18 is formed in the bent portion of the flexible circuit board 11 shown in the first embodiment. This is exactly the same as in the first embodiment.

Specifically, when the flexible circuit board 11 is a multilayer circuit board having a multilayer wiring layer, the curvature of the bent portion is ensured to be large by reducing the number of wiring layers in the bent portion as compared with other portions. be able to.
For example, the number of wiring layers other than the bent portion is four, and the number of wiring layers other than the bent portion is one.

Next, referring to FIG. 6, a semiconductor device according to a third embodiment of the present invention will be described. In the third embodiment, a metal plate for heat radiation or electromagnetic shielding is inserted between electronic components facing each other. Other configurations are the same as those in the first embodiment.
See FIG.
FIG. 6 is a configuration explanatory view of a semiconductor device according to a third embodiment of the present invention, an upper diagram is a schematic perspective view of a metal plate, and a lower diagram is a schematic side view of the folded semiconductor device. .

  As shown in the above figure, the metal plate 19 is formed by pressing a SUS plate having a thickness of 50 to 300 μm, for example, 50 μm, providing a recess 20 in a portion corresponding to the electronic component, and the opposite half of the insertion side. An engaging portion (not shown) with the metal ground layer 14 is provided in a part of the region.

As shown in the figure below, when the metal plate 19 is inserted, before the flexible circuit board 11 is folded, the recesses 20 provided in the metal plate 19 are covered with the electronic components 13 _{1 to} 13 ₆ on the electromagnetic shielding side. Then, the flexible circuit board 11 is folded together with the metal ground layer 14 at the central bent portion.
Next, the exposed end side of the metal plate 19 is bent and engaged with the metal ground layer 14 to be fixed and electrically connected.

As described above, in the third embodiment of the present invention, the metal plate 19 is inserted between the electronic components 13 _{1 to} 13 ₆ facing each other, so that electromagnetic interference between the electronic components is effectively prevented. The electronic components 13 _{1 to} 13 ₆ can be cooled by heat radiation at the same time.

Next, a semiconductor device according to a fourth embodiment of the present invention will be described with reference to FIG. 7, but the basic configuration is the same as that of the first embodiment.
See FIG.
FIG. 7 is a configuration explanatory view of a semiconductor device according to a fourth embodiment of the present invention, an upper diagram is a schematic plan view before folding, and a lower diagram is a schematic side view of the semiconductor device in a folded state. .

  As shown in the above figure, the flexible circuit board 21 having a thickness of, for example, 0.4 mm has three bent portions formed with openings 22 for taking out connector terminals or enhancing the flexibility. A metal ground layer 24 made of SUS having a thickness of 50 to 300 μm, for example, 100 μm, is fixed to the surface opposite to the mounting surface of the flexible circuit board 21.

Further, on the flexible circuit board 21, electronic components 23 ₁ to 23 ₈ such as semiconductor elements are mounted on four mounting portions separated by the opening 22.
Note that, on both side surfaces in the longitudinal direction of the metal ground layer 24, similarly to the first embodiment, cut-off portions 26 having a height substantially corresponding to the thickness of the flexible circuit board 21 are provided.

  As described above, in the fourth embodiment of the present invention, the semiconductor device is folded at three places, so that the semiconductor device can be downsized.

Next, with reference to FIG. 8, the semiconductor device according to the fifth embodiment of the present invention will be described. The basic configuration is exactly the same as the fourth embodiment.
See FIG.
FIG. 8 is a schematic side view of a semiconductor device according to a fifth embodiment of the present invention. After bending three places, a pair of opposite ends of two electronic components connected to a common radiating fin 29 at the other end. The metal plate 28 is inserted.

Further, at the other end where the radiation fins 29 are provided, the connector terminal 30 is taken out through the opening 22 and connected to the electrode terminal 31 on the electronic device casing side.
The flexible circuit board 21 is fixed to the metal ground layer 24 using a double-sided adhesive tape or an adhesive 27.

  As described above, in Example 5 of the present invention, not only the metal plate is inserted between the opposing electronic components, but also the heat radiation fins are formed at the other end, so that the cooling of the electronic components is facilitated. However, it becomes useful as a mounting structure of a semiconductor device on which more necessary electronic components are mounted.

Next, with reference to FIG. 9, the semiconductor device of Example 6 of this invention is demonstrated.
See FIG.
FIG. 9 is a configuration explanatory view of a semiconductor device according to a sixth embodiment of the present invention, an upper diagram is a schematic plan view before folding, and a lower diagram is a schematic side view of the folded semiconductor device. .

  As shown in the above figure, an opening 42 for improving flexibility is formed at a position where the length of the flexible circuit board 41 having a thickness of, for example, 0.4 mm is about 1/3. A metal ground layer 44 made of SUS having a thickness of 50 to 300 μm, for example, 100 μm, is fixed to the surface opposite to the mounting surface of the substrate 41.

However, the metal ground layer 44 in this case covers about 2/3 of the area where the opening 42 is provided, and the other 1/3 of the area remains flexible. 48.
Note that, on both side surfaces in the longitudinal direction of the metal ground layer 44, as in the first embodiment, cut-off portions 46 having a height substantially corresponding to the thickness of the flexible circuit board 41 are provided.

In addition, electronic components 43 ₁ to 43 ₆ such as semiconductor elements are mounted on the flexible circuit board 31 on both sides separated by the opening 42.
The flexible circuit board 41 is fixed to the metal ground layer 44 using a double-sided adhesive tape or an adhesive 47.

  Next, as shown in the figure below, at the position where the opening 42 is provided, the flexible circuit board 41 is folded together with the metal ground layer 44, and the connector terminal portion 48 that remains flexible is bent to be provided on the electronic device casing side. Connect to terminals (not shown) or other devices.

Thus, in Example 6 of this invention, since the part which is not covered with the metal ground layer of a flexible circuit board is made into the connector terminal, attachment of a connector terminal becomes unnecessary and a structure is simplified.

  The embodiments of the present invention have been described above. However, the present invention is not limited to the configurations and conditions described in the embodiments, and various modifications are possible. For example, in the above embodiments, Is composed of SUS having a metal ground layer and a metal plate to be inserted, which is rich in rigidity and excellent in corrosion resistance, but is not limited to SUS, and phosphor bronze, 4-2 alloy having excellent rigidity as in SUS, or It may be made of an aluminum alloy.

  Although not specifically mentioned in the sixth embodiment of the present invention, in the sixth embodiment, a metal plate may be inserted for heat dissipation or electromagnetic shielding and may be connected to a metal ground layer.

  Moreover, in Example 4 and Example 5 of this invention, although the bending location is made into three places, it is not restricted to 3 places, You may make it bend odd places, such as 5 places or 7 places. is there.

Here, the detailed description of the present invention will be described again with reference to FIG.
Again see Figure 1
(Appendix 1) A flexible circuit board 1, a plurality of electronic components 2 mounted on one surface of the circuit board 1, and a thickness of 50 μm to 300 μm fixed to the other surface of the circuit board 1 The metal plate 3 is provided with cut-out portions on both side surfaces of the metal plate 3 in the longitudinal direction, and the circuit board 1 and the metal plate 3 are arranged so that the electronic component 2 faces each other. Further, the semiconductor device is bent at bent portions respectively provided on the circuit board 1 and the metal plate 3.
(Additional remark 2) The said metal plate 3 which comprises an outer shell is stainless steel, phosphor bronze, 4-2 alloy, or aluminum alloy, The semiconductor device of Additional remark 1 characterized by the above-mentioned.
(Supplementary note 3) The semiconductor device according to Supplementary note 1 or 2, wherein the metal plate 3 is electrically connected to a ground electrode.
(Supplementary note 4) The semiconductor according to any one of supplementary notes 1 to 3, wherein a metal plate that functions as at least one of heat dissipation and electromagnetic shielding is inserted between the electronic components 2 facing each other. apparatus.
(Supplementary Note 5) The electronic component 2 includes at least two opposing portions facing each other, and the opposing portions are respectively disposed on both sides of the bent portion, and the electric component 2 of the two opposing portions is arranged. The semiconductor device according to any one of appendix 1 to appendix 4, wherein a common metal plate is inserted between each of the fins, and a heat radiating fin is formed in a part of the common metal plate.
(Additional remark 6) The said metal plate 3 is not being fixed in the one edge part side of the said circuit board 1, and the connector terminal was provided in the said one edge part side, The additional notes 1 thru | or 4 The semiconductor device according to any one of the above .

  As an application example of the present invention, a mounting structure of a semiconductor element mounted on a small electronic device such as a mobile phone or a camera is typical. However, the structure is not limited to a small electronic device, and various types including a PC. It is applied to electronic equipment.

It is a principle block diagram of this invention. It is a schematic block diagram of the flexible circuit board in the state which mounted electronic components, such as a semiconductor element of Example 1 of this invention. It is a schematic perspective view of the metal ground layer of Example 1 of this invention. It is a schematic side view of the semiconductor device of Example 1 of this invention of the folded state. It is a schematic side view of the semiconductor device of Example 2 of this invention of the folded state. It is a structure explanatory drawing of the semiconductor device of Example 3 of this invention. It is a structure explanatory view of the semiconductor device of Example 4 of the present invention. It is a schematic side view of the semiconductor device of Example 5 of the present invention. It is a structure explanatory view of the semiconductor device of Example 6 of the present invention.

Explanation of symbols

1 circuit board 2 electronic component 3 metal plates 11,21,41 flexible circuit board 12, 22, 42 opening _{131-134 6,} 23 ₁ to 23 _8, 43 ₁ to 43 ₆ electronic components 14, 24, 44 metal ground Layers 15, 25, 45 Opening portions 16, 26, 46 Standing portions 17, 27, 47 Adhesive 18 Thin portion 19 Metal plate 20 Recess 28 Metal plate 29 Radiation fin 30 Connector terminal 31 Electrode terminal 48 Connector terminal portion

Claims (4)

A flexible circuit board;
A plurality of electronic components mounted on one surface of the circuit board;
A metal plate having a thickness of 50 μm to 300 μm fixed to the other surface of the circuit board,
While the both sides of the longitudinal direction of the metal plate are provided with a cut-off portion,
The semiconductor device, wherein the circuit board and the metal plate are bent at bent portions respectively provided on the circuit board and the metal plate so that the electronic components face each other.   2. The semiconductor device according to claim 1, wherein the metal plate constituting the outer shell is one of stainless steel, phosphor bronze, 4-2 alloy, or aluminum alloy.   The semiconductor device according to claim 1, wherein the metal plate is electrically connected to a ground electrode.   4. The semiconductor device according to claim 1, wherein a metal plate that functions as at least one of heat dissipation and electromagnetic shielding is inserted between the electronic components facing each other. 5.

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