TWI559835B - Electronic device - Google Patents

Description

Electronic machine

The present invention relates to electronic machines.

In the electronic device mounted on a vehicle, for example, as a countermeasure against vibration and a countermeasure against heat dissipation, for example, as disclosed in Patent Document 1, a configuration in which various electronic components are mounted on a substrate is housed in a casing, and then a resin is used (for example, The epoxy resin is filled in the casing to encapsulate (embed) the electronic circuit including the electronic component and the substrate. Further, in the circuit of the electronic device, there is a component (power supply circuit) that directly connects to a power source such as a battery and flows a large current.

If a large current flows in an electronic component constituting such a power supply circuit and the resin around the electronic component is excessively heated, cracks may occur in the resin. This crack progresses linearly from the electronic component at the shortest distance and reaches the interface between the resin and the casing. In the prior art, in order not to expose the crack to the outside of the electronic device, a metal case (for example, an aluminum case) is used as the case.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2003-249780

However, in the case where a metal casing is used as the casing as in the above-described known technique, the weight of the electronic device is heavy, and the price of the electronic device is increased.

An aspect of the present invention is to provide an electronic device capable of suppressing the occurrence of cracks in a resin and achieving weight reduction and low cost.

An electronic device according to an aspect of the present invention includes: a substrate; an electronic component provided on a mounting surface of the substrate; and a metal cover provided on the substrate and covering the electronic component; and a housing that houses the housing And a substrate, an electronic component, and a metal cover; and a sealing resin filled in the casing, wherein the sealing resin embeds the substrate and the electronic component, and is filled in both the inner side and the outer side of the metal cover The metal cover system is constituted by a metal having a higher thermal conductivity than the above-mentioned encapsulating resin.

In an electronic device according to an aspect of the present invention, since the electronic component is covered by the metal cover, even if a crack occurs on the encapsulating resin around the electronic component, the crack proceeds to the metal cover from the direction away from the electronic component. After the inner surface, it will still proceed along the inner surface of the metal cover. That is to say, the crack does not proceed linearly to the casing, so that the crack can be prevented from reaching the interface between the encapsulating resin and the casing.

Thereby, the encapsulating resin having low heat resistance can be used, or the casing can be made into a resin case which is lighter and cheaper than metal. As described in detail, the resin case is more likely to be cracked when the crack of the encapsulating resin reaches the interface between the encapsulating resin and the case than the case of the metal case, and the crack of the encapsulating resin is exposed to the outside. Increase the thickness of the board and so on. However, as described above, by providing the metal cover, the case where the crack of the encapsulating resin reaches the interface between the encapsulating resin and the casing itself is suppressed, so even if the casing is made of resin, The thickness of the sheet can still be suppressed to be thin. Further, since the metal cover is smaller in size and lighter in weight than the metal case, it is possible to achieve weight reduction and low cost of the electronic device.

Further, in the above-described electronic device, since the metal cover system is made of a metal having a higher thermal conductivity than the sealing resin, even if a current flows through the electronic component covered by the metal cover, the package is filled inside the metal cover. The resin is locally heated and still effectively dissipates this heat in the metal shell. Therefore, it is possible to suppress the case where the encapsulating resin on the outer side of the metal cover is locally excessively heated.

Further, in the above-described electronic device, a projection protruding toward the mounting surface is formed on an inner surface of the top surface of the metal cover over the electronic component and facing the mounting surface and the electronic component It is better.

The crack that reaches the inner surface of the top plate portion is performed along the inner surface of the top plate portion. However, in the above configuration, the crack can be suppressed at the protruding portion. Further, even if it is assumed that the crack reaching the inner surface of the top plate portion passes over the projection portion along the inner surface of the top plate portion, since the distance of the crack along the inner surface of the top plate portion can be extended, the crack can be further suppressed toward the metal cover. The outside is carried out.

Further, in the above electronic device, it is preferable that the protruding portion is formed in a ring shape or a spiral shape in plan view.

In this configuration, the crack from the electronic component toward the top plate portion has an annular projection (annular projection) in plan view in the inner surface of the top plate portion or a spiral projection in plan view (vortex) After the region on the inner edge side of the protruding portion, it is easy to proceed in the circumferential direction of the annular projection or the spiral projection along the inner edge of the annular projection or the spiral projection. Therefore, the distance along the inner surface of the top plate portion can be further extended, and the crack can be prevented from proceeding toward the outer side of the metal cover.

Further, in the above electronic device, the protruding portion is formed in a plan view It is more preferable to arrange a plurality of rings in a ring shape and concentrically.

In the above configuration, even if the crack is caused to extend from the inner edge side of the inner annular projection (the annular projection in plan view) to the outer edge side, the inner edge of the outer annular projection can be extended. The distance along the crack of the inner surface of the top plate portion can further suppress the crack from proceeding to the outside of the metal cover.

Further, in the above electronic device, it is preferable that the side wall portion of the metal cover covering the side of the electronic component is in close contact with the side surface of the substrate.

In this configuration, it is possible to prevent the crack in the metal cover from proceeding from the side surface of the substrate to the side of the back surface (the surface opposite to the mounting surface).

According to an aspect of the present invention, even if the casing is made of a resin, it is possible to suppress the occurrence of cracks in the sealing resin caused by the electronic component from being exposed to the outside from the casing. Further, by making the casing made of resin, it is possible to achieve weight reduction and low cost of the electronic device.

1, 20‧‧‧Electronic machines

2‧‧‧Substrate

2a‧‧‧Mounting surface

2b‧‧‧back

2c‧‧‧ side

3‧‧‧Electronic parts

3A‧‧‧Fever parts

3B‧‧‧Electronic parts

4‧‧‧Shell

4a‧‧‧ bottom

4b‧‧‧Open end

5‧‧‧Metal cover

6‧‧‧Packaging resin

11‧‧‧ top board

12‧‧‧ Sidewall

13‧‧‧Connected holes

20‧‧‧Electronic machines

21‧‧‧Protruding

21A‧‧‧Ring protrusions (protrusions)

21B‧‧‧Vortex-shaped protrusions (protrusions)

21C‧‧‧Linear protrusions (protrusions)

31‧‧‧Semiconductor components

32‧‧‧die holder (heat sink)

100‧‧‧ adjustment circuit

101‧‧‧ Field Effect Crystal

102‧‧‧Main switch

103‧‧‧Battery

104‧‧‧Alternator

C1‧‧‧ indicates the direction of the crack from the inner surface of the top part of the heat-generating part

C2‧‧‧ shows the direction of the crack along the inner surface of the top plate

RP‧‧‧ where the rift reaches the inside of the roof

Fig. 1 is a cross-sectional view showing an electronic device according to a first embodiment of the present invention.

2 is a schematic perspective view showing the arrangement of a metal cover to a substrate in the electronic device of FIG. 1.

Fig. 3 is an explanatory view showing the direction in which cracks are generated in the encapsulating resin in the electronic device of Fig. 1.

4 is a circuit diagram showing an example of a case where an adjustment circuit is constituted by a heat-generating component provided in the electronic device of FIG. 1.

Fig. 5 is a cross-sectional view showing a principal part of an electronic device according to a second embodiment of the present invention, and is an explanatory view showing a direction in which cracks are generated in a sealing resin.

Figure 6 is a view showing the first example of the top plate portion of the metal cover in the electronic device of Figure 5; Top view.

Fig. 7 is a plan view showing a second example of the top plate portion of the metal cover in the electronic device of Fig. 5.

Fig. 8 is a plan view showing a third example of the top plate portion of the metal cover in the electronic device of Fig. 5.

Fig. 9 is a plan view showing a fourth example of the top plate portion of the metal cover in the electronic device of Fig. 5.

[First Embodiment]

Hereinafter, a first embodiment of the present invention will be described with reference to Figs. 1 to 3 .

As shown in FIGS. 1 and 2, the electronic device 1 of the present embodiment includes a substrate 2, an electronic component 3, a case 4, a metal cover 5, and a sealing resin 6.

A wiring pattern (not shown) made of, for example, copper foil or the like is formed on the substrate 2. The wiring pattern is electrically connected to the electronic components 3 mounted on the substrate 2 to form an electric circuit of the electronic device 1. The substrate 2 of the present embodiment is, for example, a multilayer wiring board in which a plurality of wiring patterns are stacked. Further, for example, as shown in FIG. 2, the substrate 2 may be formed in a rectangular shape in plan view, but is not limited thereto.

The electronic component 3 is provided on the mounting surface 2a of the substrate 2. In the present embodiment, a plurality of types of electronic components 3 (3A, 3B) are provided.

A part of the electronic component 3A is an electronic component (hereinafter referred to as a heat generating component 3A) whose heat generated by energization is high. For example, the heat generating component 3A is directly connected to a power source such as a battery, and has a large current flowing therein. Further, for example, as shown in FIG. 2, the heat generating component 3A may be provided in plural, or only one, for example. In addition, heating parts The 3A can be disposed, for example, in a region (peripheral region) near the corner of the rectangular mounting surface 2a as shown in Fig. 2, but may be disposed, for example, in a central region of the mounting surface 2a. The other electronic component 3B generates heat by energization, but the generated heat is an electronic component (for example, a capacitor) lower than the heat generating component 3A.

In the case where the electronic component 3 (particularly, the heat generating component 3A) is mounted on the die pad 32 (or the heat sink 32) of the lead frame, for example, the electronic component 3 is formed by the die pad 32. (or the heat sink 32) is attached to the mounting surface 2a of the substrate 2. Further, it is preferable that the electronic component 3 (particularly, the heat generating component 3A) is mounted on a mounting surface 2a of the substrate 2, for example, in a region overlapping the wiring pattern.

The casing 4 is a resin case 4 made of an epoxy resin or the like, and is configured to accommodate the electronic component 3 and the substrate 2 described above. In the present embodiment, the casing 4 is opened in one direction, and the electronic component 3 and the substrate 2 can be housed in the casing 4 from the opening end portion 4b of the casing 4. In the present embodiment, the mounting surface 2a of the substrate 2 faces the bottom surface 4a of the casing 4 in a state in which the substrate 2 is housed in the casing 4.

Further, in the illustrated example, the wall portion (bottom wall portion) constituting the bottom surface 4a of the casing 4 is formed in a flat plate shape, but for example, each of the electronic component 3 and the metal cover disposed on the mounting surface 2a of the substrate 2 may be fitted. The height dimension of 5 is formed into a shape having irregularities.

The metal cover 5 is housed in the casing 4 similarly to the electronic component 3 and the substrate 2 described above, and covers the electronic component 3 provided on the substrate 2. The metal cover 5 of the present embodiment is preferably made of a metal, but is preferably made of a metal having a higher thermal conductivity than a sealing resin 6 to be described later, such as a hot-dip galvanized steel sheet (SGCC).

The metal cover 5 of the present embodiment includes a top plate portion 11 that covers the upper surface of the electronic component 3, and a side wall portion 12 that covers the side portion of the electronic component 3. The side wall portion 12 is oriented from the periphery of the inner surface of the top plate portion 11 facing the mounting surface 2a of the substrate 2 and the electronic component 3. The substrate 2 extends. Further, the top plate portion 11 of the illustrated example is formed in a rectangular plate shape in plan view, but may be formed in any shape. The metal cover 5 can be formed, for example, by bending a metal plate, or by performing a drawing process. The metal cover 5 of the present embodiment covers only the heat generating component 3A of the plurality of electronic components 3.

In a state where the metal cover 5 is placed on the substrate 2, the space on the mounting surface 2a of the substrate 2 is partitioned into the inner space and the outer space of the metal cover 5. The metal cover 5 of the illustrated example is a communication hole 13 that communicates with the space inside and outside the metal cover 5 in a state where the metal cover 5 is placed on the substrate 2. The communication hole 13 is formed in order to allow the encapsulating resin 6 to flow into the inner space of the metal cover 5 . It is preferable that the communication hole 13 is a portion which is formed on the mounting surface 2a as in the example of the image formed in the metal cover. In addition, the communication hole 13 of the example is formed by cutting the front end portion of the side wall portion 12 on the mounting surface 2a side of the substrate 2, but may be formed, for example, simply by penetrating the thickness of the side wall portion 12.

Further, in the present embodiment, a part of the side wall portion 12 of the metal cover 5 extends to a lower side than the mounting surface 2a of the substrate 2 and is in close contact with the side surface 2c of the substrate 2.

In the case where the heat generating component 3A is disposed in the vicinity of the corner portion of the substrate 2 as shown in FIG. 2, the metal cover 5 is formed such that the corner portion of the top plate portion 11 having a rectangular shape in plan view coincides with the corner portion of the substrate 2. The method is disposed on the substrate 2. Accordingly, the side wall portion 12 of the metal cover 5 is formed to be in close contact with the two side faces 2c located at the corners of the substrate 2.

The metal cover 5 provided as described above can be fixed to the substrate 2 by various methods. For example, a protrusion (not shown) may be formed on the front end of the side wall portion 12 disposed on the mounting surface 2a of the substrate 2, and the protrusion may be inserted into a through hole (not shown) of the substrate 2, and then bonded to the substrate by soldering. 2 on.

The encapsulating resin 6 is filled in the casing 4 to embed the substrate 2 and the electronic component 3. Further, the encapsulating resin 6 is filled in both the inner side and the outer side of the metal cover 5 . The encapsulating resin 6 of the present embodiment is a hard potting resin which is hardened (baked) by potting from the opening end portion 4b of the casing 4 into the casing 4. Examples of such a sealing resin 6 include an epoxy resin and the like.

The electronic device 1 configured as described above can be manufactured, for example, in the following manner.

First, the electronic component 3 is placed on the mounting surface 2a of the substrate 2. Next, the metal cover 5 is fixed to the substrate 2 so as to cover the electronic component 3 (heat generating component 3A). Then, the substrate 2, the electronic component 3, and the metal cover 5 are housed in the casing 4 from the opening end portion 4b. Next, the encapsulating resin 6 is poured into the casing 4 from the opening end portion 4b by potting, and then hardened to complete the manufacture of the electronic device 1.

When the encapsulating resin 6 flows into the casing 4, the encapsulating resin 6 flows into the inner side of the metal casing 5 from the communication hole 13 of the metal casing 5, and the sealing resin 6 can be filled not only on the outer side of the metal casing 5. It can also be filled on the inside.

In the electronic device 1 of the present embodiment, when the sealing resin 6 around the heat generating component 3A is excessively heated by the large current passing through the heat generating component 3A or the like, cracks are generated in the sealing resin 6 around the heat generating component 3A. When the crack is generated on the sealing resin 6 on the mounting surface 2a side of the substrate 2, as shown in FIG. 3, the crack proceeds in the direction away from the heat generating component 3A and reaches the inner surface of the metal cover 5. This crack is often caused by the heat generating component 3A toward the inner surface of the top plate portion 11. Further, reference numeral C1 in Fig. 3 indicates the direction in which the crack from the heat generating component 3A toward the inner surface of the top plate portion 11 is made.

Further, after the crack reaches the inner surface of the metal cover 5, it proceeds along the inner surface of the metal cover 5. That is to say, the crack does not linearly proceed to the casing 4, so that the crack can be prevented from reaching the interface between the encapsulating resin 6 and the casing 4. Further, the symbol C2 in Fig. 3 indicates the direction in which the crack along the inner surface of the top plate portion 11 is proceeding.

Therefore, according to the electronic device 1 of the present embodiment, even if the casing 4 is a ratio The metal is made of a lightweight and inexpensive resin, and it is possible to prevent the crack from being exposed to the outside of the casing 4. Further, since the metal cover 5 is smaller in size and lighter than the metal case 4, and the thickness of the resin case 4 can be suppressed to be thin, the weight reduction of the electronic device 1 can be achieved. Low price.

In the electronic device 1 of the present embodiment, the heat generating component 3A is provided with the die pad 32 (heat radiating plate 32), or the heat generating component 3A is mounted on the mounting surface 2a of the substrate 2 in a region overlapping the wiring pattern. Then, even if the heat of the heat generating component 3A acts on the substrate 2 side, the heat can be absorbed in the die pad 32 (heat radiating plate 32) of the heat generating component 3A or the wiring pattern formed on the substrate 2. As a result, it is possible to suppress or prevent cracking in the sealing resin 6 on the side of the back surface 2b of the substrate 2 on the side opposite to the mounting surface 2a.

Further, when the wiring pattern of the substrate 2 is placed at a high density in the mounting region of the heat generating component 3A by a copper foil or the like, the heat of the heat generating component 3A can be more effectively prevented from being conducted to the back surface 2b side of the substrate 2. In particular, when the substrate 2 is a multilayer wiring board, it is possible to easily increase the density of the wiring pattern, and it is possible to more reliably prevent the occurrence of cracks in the sealing resin 6 on the back surface 2b side of the substrate 2.

Further, according to the electronic device 1 of the present embodiment, since one of the side wall portions 12 of the metal cover 5 is in close contact with the side surface 2c of the substrate 2, it is possible to prevent the crack in the metal cover 5 from being formed on the side surface 2c of the substrate 2. Go to the back 2b side.

Further, according to the electronic device 1 of the present embodiment, since the crack is not formed on the sealing resin 6 on the back surface 2b of the sealing substrate 2, it is not necessary to close the opening end portion 4b of the casing 4 by a metal lid or the like. Therefore, the weight reduction and low price of the electronic device 1 can be achieved.

Further, according to the electronic device 1 of the present embodiment, since the thermal conductivity of the metal cover 5 is higher than that of the encapsulating resin 6, even if the electric current passes through the heat generating component 3A, the filling is performed. The encapsulating resin 6 on the inner side of the metal cover 5 is locally heated, and this heat can be efficiently diffused in the metal cover 5. Thereby, it is possible to suppress the partial sealing of the encapsulating resin 6 on the outer side of the metal cover 5 to be excessively heated. Therefore, it is possible to more reliably suppress the occurrence of cracks in the sealing resin 6 on the outer side of the metal cover 5.

Further, in the electronic device 1 of the present embodiment, when the metal cover 5 is electrically connected to the ground wiring of the substrate 2, the influence of the electromagnetic noise of the heat generating component 3A on the outer side of the metal cover 5 can be prevented. Other electronic parts 3B.

Further, in the case where the heat generating component 3A constitutes the field effect transistor (FET) 101 of the adjusting circuit 100 illustrated in FIG. 4, the structure of the electronic device 1 of the present embodiment particularly functions.

Specifically, when the heating element 3A constitutes the adjustment circuit 100, even if the main switch 102 is turned off (OFF), the voltage of the battery 103 is supplied to the heat generating component 3A for a long time. Further, in a state where the engine (not shown) of the vehicle on which the electronic device 1 is mounted is driven, the voltage of the alternator (ACG) 104 is supplied to the heat generating component 3A for a long time. In other words, when the heating element 3A constitutes the adjustment circuit 100, since the heat generating component 3A continues to generate heat for a long period of time, the structure of the electronic device 1 of the present embodiment can function very much.

Further, in the electronic device 1 of the first embodiment, the communication hole 13 is not limited to the side wall portion 12 formed on the metal cover 5, and may be formed, for example, in the top plate portion 11. In this case, for example, after the sealing resin 6 is directly flowed from the communication hole 13 into the inner space of the metal cover 5, the communication hole 13 may be closed by a cap made of metal or the like. Further, after the encapsulating resin 6 is directly flowed into the inner space of the metal cover 5, the encapsulating resin 6 is filled in the casing 4, and the outer space of the metal cover 5 is buried in the encapsulating resin 6.

Further, for example, the metal cover 5 of the first embodiment may not be formed. The communication hole 13 described above. Even in such a configuration, the encapsulating resin 6 can flow into the inside of the metal cover 5. Specifically, in the above-described configuration, the entire front end portion of the side wall portion 12 of the metal cover 5 on the mounting surface 2a of the substrate 2 is brought into contact with the mounting surface 2a, but actually the metal cover 5 is used. A slight gap is formed between the front end portion of the side wall portion 12 and the mounting surface 2a, such as the dimensional tolerance of the mounting surface 2a of the substrate 2. Therefore, when the viscosity of the encapsulating resin 6 is extremely low, the encapsulating resin 6 can flow into the inner side of the metal cover 5 from a minute gap.

[Second embodiment]

Hereinafter, a second embodiment of the present invention will be described with reference to Figs. 5 to 9 .

As shown in Fig. 5, the electronic device 20 of the present embodiment is configured similarly to the electronic device 1 of the first embodiment except for the shape of the metal cover 5. In the present embodiment, only the differences from the first embodiment will be described, and the same components as those in the first embodiment will be denoted by the same reference numerals and the description will be omitted.

In the electronic device 20 of the present embodiment, similarly to the first embodiment, a part of the side wall portion 12 of the metal cover 5 is in close contact with the side surface 2c of the substrate 2.

Further, the side wall portion 12 of the metal cover 5 of the present embodiment may be formed to have a communication hole 13 similar to that of the first embodiment (see FIGS. 1 and 2). For example, as shown in FIG. The front end portions of the side wall portions 12 of the metal cover 5 on the mounting surface 2a of the second surface 2a are formed to be in contact with the mounting surface 2a.

In the metal cover 5 of the electronic device 20 of the present embodiment, the inner surface of the top plate portion 11 facing the mounting surface 2a of the substrate 2 and the heat generating component 3A is formed with a protruding portion that protrudes toward the mounting surface 2a. twenty one. Further, the projections 21 of the illustrated example are formed by imprinting from the outer surface of the top plate portion 11 which constitutes the outer surface of the metal cover 5 Formed, but not limited to this. In the present embodiment, the projections 21 are formed to be spaced apart from each other along the inner surface.

Hereinafter, a specific example of the planar shape of the protrusions 21 (21A to 21C) formed on the substrate 2 will be described with reference to FIGS. 6 to 9 .

The protrusion 21A of the first example shown in Fig. 6 is formed in a ring shape in plan view. In this plan view, the annular projection 21A (hereinafter referred to as the annular projection 21A) may be formed, for example, only one. However, as shown in FIG. 6, for example, a plurality of projections 21A may be arranged in a concentric manner. Further, it is preferable that the center of the annular projecting portion 21A overlaps with the center of each of the heat generating components 3A in a plan view. In FIG. 6, the annular projection 21A is formed centering on the central region of the inner surface of the top plate portion 11, but is not limited thereto. In addition, the annular projection 21A shown in FIG. 6 is formed in a rectangular shape in a plan view in a plan view of the top plate portion 11. However, the present invention is not limited thereto, and may be formed in an annular shape in plan view, for example.

Similarly to the protrusion 21A of the first example, the protrusion 21A of the second example shown in FIG. 7 is formed in a ring shape in plan view. Further, the annular projection 21A of the second example is arranged in a plurality of concentric shapes. However, the annular projections 21A of the second example are arranged at a plurality of intervals along the inner surface of the top plate portion 11 (two in the illustrated example). In the example of the figure, a plurality of groups (annular projection groups) of a plurality of annular projections 21A arranged in a concentric manner are arranged in a plurality (two) along the inner surface of the top plate portion 11. In addition, the number of the array of the annular projections can be overlapped by the metal cover 5 as shown in the example of the example in which the center of each of the annular projections overlaps with the center of each of the heat-generating components 3A in plan view. The number of heat-generating parts 3A.

The projection 21B of the third example shown in Fig. 8 is formed in a spiral shape in plan view. The spiral-shaped projections 21B (hereinafter referred to as the spiral-shaped projections 21B) may be arranged at intervals along the inner surface of the top plate portion 11, for example, as in the configuration shown in Fig. 7, but for example, As shown in Fig. 8, only one can be formed. Further, with the spiral protrusion 21B It is preferable that the center portion overlaps with the center of each of the heat generating parts 3A in a plan view.

In addition, in FIG. 8, one spiral-shaped protrusion part 21B is formed centering on the center area of the inner surface of the top plate part 11, but it is not limited to this. Further, the spiral projection 21B shown in FIG. 8 is linearly extended and curved in a plan view of the top plate portion 11, but may be formed in an arc shape, for example.

The projection 21C of the fourth example shown in Fig. 9 is formed in a straight line shape in plan view. Further, in the configuration shown in Fig. 9, a plurality of linear projections 21C (hereinafter referred to as linear projections 21C) are formed. Further, the plurality of linear projections 21C shown in FIG. 9 are arranged in parallel with each other, but they may be alternately arranged.

According to the electronic device 1 of the present embodiment, the same effects as those of the first embodiment can be obtained.

Further, according to the electronic device 1 of the present embodiment, since the projections 21 are formed on the inner surface of the top plate portion 11, it is possible to suppress the progress of the cracks reaching the inner surface of the top plate portion 11 along the inner surface of the top plate portion 11. That is to say, the projections 21 can function as a shield for suppressing the progress of cracks. Further, even if it is assumed that the crack reaching the inner surface of the top plate portion 11 passes over the projection portion 21 and proceeds along the inner surface of the top plate portion 11, the distance of the crack along the inner surface of the top plate portion 11 can be extended. Therefore, compared with the electronic device 1 of the first embodiment, it is possible to further suppress the progress of the crack toward the outer side of the metal cover 5.

Further, since the projections 21 (21A to 21C) of the present embodiment (first to fourth examples) extend in a plan view in a plan view, the cracks along the inner surface of the top plate portion 11 reach the extending direction of the projections 21. After the intermediate portion, as shown in FIGS. 6 to 9, it becomes easy to proceed in the extending direction of the projection 21. Further, the symbol RP exemplifies the position at which the crack reaches the inner surface of the top plate portion 11. Further, the symbol C2 in FIGS. 6 to 9 exemplifies the direction in which the crack progresses from the inner surface of the top plate portion 11 from the arrival position RP. Thereby, the extension along the top plate portion 11 can be further extended The distance between the cracks on the inside surface.

In particular, in the case of the annular projection 21A and the spiral projection 21B of the first to third examples, as shown in FIGS. 6 to 8, the crack from the heat generating component 3A to the top plate portion 11 reaches the top plate portion. After the annular projection 21A or the region on the inner edge side of the spiral projection 21B in the inner surface of the 11 is easily formed along the inner edge of the annular projection 21A or the spiral projection 21B toward the annular projection 21A or The spiral protrusion 21B is circumferentially formed. Therefore, the distance of the crack along the inner surface of the top plate portion 11 can be further extended as compared with the case of the linear projection portion 21C.

Further, in the configuration of the first and second examples, when the annular projections 21A are arranged in a plurality of concentric shapes, as shown in FIGS. 6 and 7, even if the cracks are assumed to be from the inner annular projections 21A, The inner edge side is moved over the outer edge side, and since the inner edge of the outer annular projection 21A is reached, the crack along the inner surface of the top plate portion 11 can be further extended as compared with the case where only one annular projection 21A is formed. Make the distance.

Further, in the case of the spiral projection 21B of the third example, similarly to the case where the plurality of annular projections 21A are arranged concentrically, a plurality of projections are arranged in the radial direction, so that, as shown in FIG. A similar effect can be obtained.

Further, as shown in the first to third examples, the center of the annular projection 21A or the spiral projection 21B is overlapped with the center of each of the heat generating components 3A in a plan view, and the crack easily reaches the top plate portion 11. The inner edge side of the annular projection 21A in the inner surface and the inner edge side of the radially inner projection portion of the spiral projection 21B can effectively extend the crack along the inner surface of the top plate portion 11. distance.

The embodiments of the present invention have been described in detail above, but the present invention is not limited to the embodiments described above, and various modifications may be made without departing from the spirit and scope of the invention.

For example, the metal cover 5 is not only used to cover the heat generating component 3A, but may cover other electronic components 3B. Further, the metal cover 5 is not limited to covering only one portion of the mounting surface 2a of the substrate 2, and may cover the entire mounting surface 2a, for example. Further, when the metal cover 5 covers the entire mounting surface 2a, the entire side wall portion 12 of the metal cover 5 can be in close contact with the side surface 2c of the substrate 2.

In these cases, since the area covered by the metal cover 5 is larger than that of the embodiment, it is possible to further prevent the crack of the sealing resin 6 generated inside the metal cover 5 from proceeding to the outside of the metal cover 5. Happening.

In addition, the substrate 2 is not limited to being housed so that the mounting surface 2a faces the bottom surface 4a of the casing 4, and may be housed in the casing 4 in a state in which the mounting surface 2a faces an arbitrary direction. For example, the substrate 2 can be housed in the casing 4 such that the mounting surface 2a faces the opening end portion 4b side of the casing 4.

(industrial availability)

According to the electronic device of one aspect of the present invention, it is possible to suppress the occurrence of cracks in the encapsulating resin from being exposed outside the casing, and it is possible to achieve weight reduction and low cost.

1‧‧‧Electronic machines

2‧‧‧Substrate

2a‧‧‧Mounting surface

2b‧‧‧back

2c‧‧‧ side

3‧‧‧Electronic parts

3A‧‧‧Fever parts

3B‧‧‧Electronic parts

4‧‧‧Shell

4a‧‧‧ bottom

4b‧‧‧Open end

5‧‧‧Metal cover

6‧‧‧Packaging resin

11‧‧‧ top board

12‧‧‧ Sidewall

13‧‧‧Connected holes

Claims (5)

An electronic device comprising: a substrate; an electronic component provided on a mounting surface of the substrate; a metal cover provided on the substrate and covering the electronic component; and a housing accommodating the substrate and the electronic component And a metal encapsulant; and a sealing resin filled in the casing, wherein the encapsulating resin embeds the substrate and the electronic component, and fills both the inner side and the outer side of the metal cover, and the metal cover system It is composed of a metal having a higher thermal conductivity than the above-mentioned encapsulating resin. The electronic device according to claim 1, wherein the mounting surface is formed on the inner surface of the top surface of the metal cover over the electronic component and facing the mounting surface and the electronic component And prominent protrusions. The electronic device according to claim 2, wherein the protrusions are formed in a ring shape or a spiral shape in plan view. The electronic device according to claim 3, wherein the protrusions are formed in a plurality of shapes in a ring shape in a plan view and concentrically arranged. The electronic device according to any one of claims 1 to 4, wherein a side wall portion of the metal cover covering the side of the electronic component is in close contact with a side surface of the substrate.