WO2021215187A1

WO2021215187A1 - Electronic device

Info

Publication number: WO2021215187A1
Application number: PCT/JP2021/012596
Authority: WO
Inventors: 岳史石川
Original assignee: 株式会社デンソー
Priority date: 2020-04-23
Filing date: 2021-03-25
Publication date: 2021-10-28
Also published as: JP2021174847A

Abstract

An electronic device (1) comprises: a printed circuit board (2), a plurality of electronic components (3-5) that is mounted on the printed circuit board and has different heights; a lid (6) that is configured of a metal material, covers the plurality of electronic components, and is grounded with respect to the printed circuit board; a first heat radiating member (16) provided between the lid and at least one electronic component from which heat is to be radiated from among the plurality of electronic components; a heat sink (7) provided above the lid; and a second heat radiating member (19) provided between the lid and the heat sink. The upper surface of the lid is shaped to have a step according to the height of the plurality of electronic components.

Description

Electronics

Cross-reference of related applications

This application is based on Japanese Application No. 2020-076710, which was filed on April 23, 2020, and the contents of the description are incorporated herein by reference.

This disclosure relates to electronic devices.

Conventionally, along with the increasing functionality and performance of electronic devices, the performance and speed of electronic components mounted on electronic devices have been increasing, and power consumption is expected to increase. For example, Patent Document 1 discloses a configuration in which heat generated from an electronic component is transferred to a heat sink via a heat radiating member in order to improve the heat dissipation of the electronic component. Further, for example, Patent Document 2 has a configuration in which a shield member is used to connect a lid for heat dissipation of an electronic component to a printed circuit board in order to achieve both EMC (Electromagnetic Compatibility) measures and improvement of heat dissipation of the electronic component. It is disclosed.

Japanese Patent No. 5983032 Japanese Unexamined Patent Publication No. 2012-164852

There are fans, heat sinks, and heat dissipation members as means for improving the heat dissipation of electronic components, and it is conceivable to improve these means. As for the fan, if it is attempted to improve the cooling performance, there is a concern that the power consumption of the motor and the driving noise will increase, so it is difficult to adopt a method for improving the fan. As for the heat sink, in order to improve the heat transfer performance, it is necessary to optimize it according to the design requirements such as the area of the heat sink and the number of heat radiation fins, so there is a limit to the method for improving the heat sink. As for the heat radiating member, high thermal conductivity of the material is considered, but there are concerns about problems such as high cost and high interfacial thermal resistance with the heat sink, and it is difficult to adopt a method for improving the heat radiating member.

Under these circumstances, consider the fan, heat sink, and heat dissipation member as a whole, not as individual elements, how to transfer the heat generated from the electronic components to the heat sink, and how to reduce the thermal resistance from the electronic components to the heat sink. The issue is how to reduce it. In general, thermal resistance, like electrical resistance, is proportional to the thermal conductivity and thickness of the material and inversely proportional to the area. Therefore, in order to reduce the thermal resistance, it is effective to reduce the thickness of the heat radiating member or increase the area.

Regarding the thickness of the heat dissipation member, there is a method of reducing the thickness of the heat dissipation member by applying downward pressure to the heat sink, but in that case, stress is applied to the solder bumps of the electronic components and cracks occur. There is a concern that it may break or break. Further, regarding the area of the heat radiating member, since the size of the electronic component is fixed, there is a limit to the area that can be expanded. Therefore, a method of expanding the heat dissipation area by attaching a metal heat spreader to the electronic component is envisioned.

On the other hand, with regard to EMC countermeasures, fine wiring is required as the performance and speed of electronic components increase, and wiring must be routed to the surface layer of the printed circuit board. Therefore, it is necessary not only to shield only the electronic components but also to shield the area including the electronic components and the surrounding fine wiring, and the lid covering the area including the electronic components and the surrounding fine wiring is used as a heat spreader. Is assumed. The lid must be grounded for the shield. Further, in the configuration in which the lid is used as a heat spreader, a first heat radiating member is provided between the electronic component to be radiated and the lid needs to dissipate heat, and a second heat radiating member is provided between the lid and the heat sink. It becomes.

By the way, when a plurality of electronic components are mounted on a printed circuit board, a lid is provided so as to cover the plurality of electronic components. In this case, the heights of the plurality of electronic components are not always the same, the heights may differ, and the height of the electronic components to be dissipated is not always the maximum among the plurality of electronic components. If the height of the electronic component to be radiated is lower than that of other electronic components, the thickness of the first heat radiating member provided between the electronic component to be radiated and the lid becomes thick to some extent, and the heat radiating property may be deteriorated. There is. Further, since the number of electronic components to be radiated is not limited to one, the heat radiating property may be deteriorated even if the thickness of the first heat radiating member varies. Under these circumstances, in a configuration in which a plurality of electronic components having different heights are mounted on a printed circuit board, it is desired to appropriately suppress radiation noise from the plurality of electronic components and appropriately improve heat dissipation. It is rare.

An object of the present disclosure is to appropriately suppress radiation noise from a plurality of electronic components and appropriately improve heat dissipation in a configuration in which a plurality of electronic components having different heights are mounted on a printed circuit board. ..

According to one aspect of the present disclosure, it is composed of a printed circuit board, a plurality of electronic components having different heights, and a metal material, which are mounted on the printed circuit board, cover the plurality of electronic components, and are grounded to the printed circuit board. The lid, the first heat-dissipating member provided between the lid and at least one electronic component to be dissipated from the plurality of electronic components, the heat sink provided above the lid, and the lid. A second heat radiating member provided between the heat sink and the heat sink is provided. The upper surface of the lid has a shape having a step according to the height of a plurality of electronic components.

Since the lid is grounded to the printed circuit board, even if noise current is induced in the lid by electromagnetic waves radiated from multiple electronic components, the induced noise current is discharged to the grounded part. Therefore, radiation noise can be suppressed. Since the upper surface of the lid has a stepped shape according to the height of a plurality of electronic components, even if the height of the electronic component to be radiated is lower than that of other electronic components, the electronic component and the lid to be radiated are radiated. By forming a step so as to narrow the distance between the two, the thickness of the first heat radiating member can be suppressed, and deterioration of heat radiating property can be avoided in advance. As a result, in a configuration in which a plurality of electronic components having different heights are mounted on the printed circuit board, radiation noise from the plurality of electronic components can be appropriately suppressed and heat dissipation can be appropriately improved.

According to one aspect of the present disclosure, a first printed circuit board, a second printed circuit board mounted on the first printed circuit board, and a plurality of electronic components mounted on the second printed circuit board and having different heights. A lid made of a metal material, which covers a plurality of electronic components and is grounded to a second printed circuit board, is provided between the lid and at least one electronic component to be dissipated from the plurality of electronic components. It includes a first heat radiating member provided, a heat sink provided above the lid, and a second heat radiating member provided between the lid and the heat sink. The upper surface of the lid has a shape having a step according to the height of a plurality of electronic components.

Since the lid is grounded to the second printed circuit board, even if a noise current is induced in the lid by electromagnetic waves radiated from a plurality of electronic components, the induced noise current is discharged to the grounded portion. By doing so, radiation noise can be suppressed. Since the upper surface of the lid has a stepped shape according to the height of a plurality of electronic components, even if the height of the electronic component to be radiated is lower than that of other electronic components, the electronic component and the lid to be radiated are radiated. By forming a step so as to narrow the distance between the two, the thickness of the first heat radiating member can be suppressed, and deterioration of heat radiating property can be avoided in advance. As a result, even in a configuration in which the second printed circuit board is mounted on the first printed circuit board and a plurality of electronic components having different heights are mounted on the second printed circuit board, radiation noise from the plurality of electronic components can be appropriately generated. While suppressing it, the heat dissipation can be appropriately improved.

According to one aspect of the present disclosure, a first printed circuit board, a second printed circuit board mounted on the first printed circuit board, and a plurality of electronic components mounted on the second printed circuit board and having different heights. A lid made of a metal material, which covers a plurality of electronic components and is grounded to a first printed circuit board, is provided between the lid and at least one electronic component to be dissipated from the plurality of electronic components. It includes a first heat radiating member provided, a heat sink provided above the lid, and a second heat radiating member provided between the lid and the heat sink. The upper surface of the lid has a shape having a step according to the height of a plurality of electronic components.

Since the lid is grounded to the first printed circuit board, even if a noise current is induced in the lid by electromagnetic waves radiated from a plurality of electronic components, the induced noise current is discharged to the grounded portion. By doing so, radiation noise can be suppressed. Since the upper surface of the lid has a stepped shape according to the height of a plurality of electronic components, even if the height of the electronic component to be radiated is lower than that of other electronic components, the electronic component and the lid to be radiated are radiated. By forming a step so as to narrow the distance between the two, the thickness of the first heat radiating member can be suppressed, and deterioration of heat radiating property can be avoided in advance. As a result, even in a configuration in which the second printed circuit board is mounted on the first printed circuit board and a plurality of electronic components having different heights are mounted on the second printed circuit board, radiation noise from the plurality of electronic components can be appropriately generated. While suppressing it, the heat dissipation can be appropriately improved.

The above objectives and other objectives, features and advantages of the present disclosure will be clarified by the following detailed description with reference to the accompanying drawings. The drawing is
FIG. 1 is a vertical sectional side view showing the first embodiment. FIG. 2 is a cross-sectional plan view. FIG. 3 is a longitudinal side view showing another configuration of the first embodiment. FIG. 4 is a longitudinal side view showing another configuration of the first embodiment. FIG. 5 is a longitudinal side view showing another configuration of the first embodiment. FIG. 6 is a cross-sectional plan view. FIG. 7 is a vertical sectional side view showing the second embodiment. FIG. 8 is a longitudinal side view showing another configuration of the second embodiment. FIG. 9 is a longitudinal side view showing another configuration of the second embodiment. FIG. 10 is a longitudinal side view showing another configuration of the second embodiment. FIG. 11 is a vertical sectional side view showing the third embodiment. FIG. 12 is a cross-sectional plan view. FIG. 13 is a longitudinal side view showing another configuration of the third embodiment. FIG. 14 is a vertical sectional side view showing the fourth embodiment. FIG. 15 is a longitudinal side view showing another configuration of the fourth embodiment. FIG. 16 is a vertical sectional side view showing the fifth embodiment. FIG. 17 is a cross-sectional plan view. FIG. 18 is a vertical sectional side view showing the sixth embodiment. FIG. 19 is a cross-sectional plan view.

Hereinafter, some embodiments of the electronic device will be described with reference to the drawings. In each of the following embodiments, the same reference numerals may be given to the parts corresponding to the contents described in the preceding embodiments, and duplicate description may be omitted. In addition, in FIG. 1 and the like, the A1 direction will be described as upward and the A2 direction will be described as downward.

(First Embodiment)
The first embodiment will be described with reference to FIGS. 1 to 6. FIG. 2 shows a cross-sectional plane along the X1-X2 direction in FIG. The electronic device 1 is, for example, an in-vehicle electronic device mounted on a vehicle, and includes a printed circuit board 2, a plurality of (three in this embodiment) electronic components 3 to 5 mounted on the printed circuit board 2. A lid 6 and a heat sink 7 are provided. The electronic components 3 to 5 are, for example, ball grid array package type (BGA type) semiconductor elements, in which the semiconductor chip and the package substrate are electrically connected by bonding wires and as a whole by a resin mold on the upper surface side of the package substrate. It is formed as a thin rectangular package.

In the electronic components 3 to 5, solder bumps 8 to 10 are provided on the mounting surface (lower surface in FIG. 1) of the package substrate by a large number of solder balls. For the solder balls, lead-free solder using an alloy such as tin, silver, or copper can be applied. In the present embodiment, the electronic component 3 is, for example, a SoC (System on Chip), the electronic component 4 is, for example, a power supply IC (Integrated Circuit), and the electronic component 5 is, for example, a memory element. The electronic component 3 and the electronic component 4 are electrically connected by wiring 11 on the surface of the printed circuit board 2. The electronic component 3 and the electronic component 5 are electrically connected by wiring 12 on the surface of the printed circuit board 2. When the electronic components 3 to 5 are mounted on the printed circuit board 2, the height of the electronic components 3 is lower than the height of the

electronic components

4 and 5. Further, the calorific value of the electronic components 3 is larger than the calorific value of the

electronic components

4 and 5. In the present embodiment, the electronic component 3 is an electronic component to be heat-dissipated that requires heat dissipation.

The printed circuit board 2 is a multilayer substrate in which insulating substrates such as epoxy resin containing glass fibers are laminated in multiple layers, and a conductor pattern is formed on the surface and between layers thereof, and a ground pattern is formed between the layers. Has been done. The surface of the printed circuit board 2 is provided with a land for conduction for solder-bonding the electronic components 3 to 5 corresponding to the solder bumps 8 to 10 of the electronic components 3 to 5 described above, and the lid 6 is provided. There is a grounding land for the grounding. Further, on the surface of the printed circuit board 2, a solder resist layer is provided so as to cover a portion excluding the land for conduction and the land for grounding. The solder resist layer is formed as an outermost layer that protects the conductor pattern and the insulating base material on the surface of the printed circuit board 2 and exposes the land for conduction and the land for grounding. A printed body is provided on the land for conduction and the land for grounding by printing a solder paste using a printing mask. Further, the land for grounding is conducting with the ground pattern via the via.

In the process of mounting the electronic components 3 to 5 on the printed circuit board 2, the solder bumps 8 to 10 of the electronic components 3 to 5 are aligned and overlapped with respect to the land for conduction, and heated while controlling the temperature to perform solder bonding. conduct. This heating is performed through a reflow oven (not shown). The printed matter, which is a solder paste, and the solder bumps 8 to 10 are melted and integrated, and then cooled to solidify the solder to form a solder joint, whereby the electronic components 3 to 5 are formed on the printed circuit board 2. It is electrically and physically connected to the solder bumps 8 to 10 via solder bumps 8 to 10.

The lid 6 is provided so as to cover the electronic components 3 to 5 and the

wirings

11 and 12 from above. The lid 6 is made of a metal material such as aluminum or copper, and has a concave shape having a hollow portion 15 formed of an upper surface portion 13 and a side surface portion 14. That is, the electronic components 3 to 5 are housed in the hollow portion 15. Here, as shown in FIG. 2, the upper surface portion 13 has a shape having a step according to the height of the electronic components 3 to 5. That is, the upper surface portion 13 has a portion corresponding directly above the electronic component 3 having a height lower than that of the

electronic components

4 and 5, which is recessed downward, so that the lower portion 13a corresponding directly above the electronic component 3 and the electronic component 13 are formed. It has a shape having an upper portion 13b corresponding to directly above the

components

4 and 5.

A first heat radiating member 16 is provided between the electronic component 3 and the lower portion 13a on the upper surface portion 13 of the lid 6. That is, in the present embodiment, the first heat radiating member 16 is provided between the electronic component 3 and the lid 6, which have the largest heat generation amount among the electronic components 3 to 5. The first heat radiating member 16 is, for example, a heat radiating gel molded into a sheet shape. Since the first heat radiating member 16 is provided, most of the heat generated from the electronic component 3 is directly transferred to the first heat radiating member 16 and is transferred from the first heat radiating member 16 to the upper surface portion 13 of the lid 6.

In the process of mounting the lid 6 on the printed circuit board 2, the lower end portion of the side surface portion 14 of the lid 6 is aligned with the ground for grounding, overlapped, heated while controlling the temperature, and solder-bonded. When the solder solidifies to form a solder joint, the lid 6 is physically connected to the printed circuit board 2 and grounded. When the lid 6 is mounted on the printed circuit board 2, the surface direction of the upper surface portion 13 of the lid 6 and the surface direction of the printed circuit board 2 are substantially parallel.

The heat sink 7 is provided above the lid 6. The heat sink 7 is made of a metal material such as aluminum or copper, and has a base plate 17 and a plurality of heat radiation fins 18. The base plate 17 has a flat plate shape that extends in the plane direction of the upper surface portion 13 of the lid 6. Each of the heat radiating fins 18 is a thin plate-shaped heat radiating plate, which is erected vertically from the base plate 17 and arranged substantially parallel to each other, and a ventilation path is formed between adjacent heat radiating fins 18.

A second heat radiating member 19 is provided between the upper surface portion 13 of the lid 6 and the base plate 17 of the heat sink 7. Like the first heat radiating member 16, the second heat radiating member 19 is, for example, a heat radiating gel formed in a sheet shape. Since the second heat radiating member 19 has a shape in which the upper surface portion 13 of the lid 6 has a step as described above, the portion directly above the electronic component 3 corresponds to the shape of the upper surface portion 13 of the lid 6 downward. It is recessed and has a stepped shape. That is, the thickness of the second heat radiating member 19 is uniform in the plane direction. Since the second heat radiating member 19 is provided, most of the heat transferred from the electronic component 3 to the lid 6 via the first heat radiating member 16 is directly transferred to the second heat radiating member 19 and from the second heat radiating member 19. It is transmitted to the base plate 17. Then, most of the heat transferred to the base plate 17 is transferred to the heat radiation fins 18 and diffused from the heat radiation fins 18. Since the base plate 17 of the heat sink 7 has a shape in which the second heat radiating member 19 has a step, the thickness of the base plate 17 is not uniform in the plane direction. That is, in the base plate 17, the portion corresponding to the lower portion 13a of the upper surface portion 13 is relatively thick, and the portion corresponding to the upper portion 13b of the upper surface portion 13 is relatively thin.

The heat sink 7 is fixed to the printed circuit board 2 by the fastening member 20. The fastening member 20 includes a bolt 21, a spring 22, a nut 23, and the like, and is arranged at four corners of a base plate 17 in, for example, a heat sink 4. Through holes 24 through which bolts 21 are inserted are provided at the four corners of the base plate 17. Further, at the four corners of the printed circuit board 2, through holes 25 corresponding to the through holes 24 of the base plate 17 and through which the bolts 21 are inserted are provided. A bolster plate 26 is arranged on the back surface side of the printed circuit board 2. One end side (lower end side in FIG. 1) of the bolt 21 is connected to the bolster plate 26 via a fixing tool 27 such as a driving screw. A nut 23 and a spring 22 are mounted on the other end side (upper end side in FIG. 1) of the bolt 21, and the spring 22 is compressed by tightening the nut 23. In this case, the restoring force of the spring 22 presses the heat sink 7 against the printed circuit board 2. That is, the heat sink 7 is fastened to the printed circuit board 2 by the fastening member 20, and the heat sink 7 is fixed to the printed circuit board 2 in a state where a pressing force is applied to the printed circuit board 2 side.

In the above configuration, since the upper surface portion 13 of the lid 6 has a stepped shape, the distance between the electronic component 3 having the largest calorific value among the electronic components 3 to 5 and the upper surface portion 13 of the lid 6 is narrowed. The thickness of the first heat radiating member 16 between the electronic component 3 and the lid 6 is suppressed. That is, since the height of the lid 6 is designed according to the electronic component having the highest height among the electronic components 3 to 5, the electronic component 3 and the lid have a shape in which the upper surface portion 13 of the lid 6 does not have a step. The distance from the upper surface portion 13 of 6 becomes wider. In that case, the thickness of the first heat radiating member 16 between the electronic component 3 and the lid 6 becomes thick to some extent, and there is a risk that the heat radiating property deteriorates. On the other hand, in the present embodiment, the upper surface portion 13 of the lid 6 has a stepped shape, and the thickness of the first heat radiating member 16 is suppressed to prevent deterioration of heat radiating property.

According to the first embodiment, the following effects can be obtained. Since the lid 6 is grounded to the printed circuit board 2 in the electronic device 1, even if a noise current is induced in the lid 6 by electromagnetic waves radiated from the electronic components 3 to 5, the induced noise is induced. Radiation noise can be suppressed by discharging the current to the grounded portion. Since the upper surface portion 13 of the lid 6 has a stepped shape, even if the height of the electronic component 3 to be dissipated is lower than that of the other

electronic components

4 and 5, the electronic component 3 to be dissipated and the lid 6 are still in contact with each other. By forming a step so as to narrow the distance, the thickness of the first heat radiating member 16 can be suppressed, and deterioration of heat radiating property can be avoided in advance. As a result, in a configuration in which a plurality of electronic components 3 to 5 having different heights are mounted on the printed circuit board 2, radiation noise from the plurality of electronic components 3 to 5 is appropriately suppressed and heat dissipation is appropriately improved. Can be made to. In this case, since a part of the upper surface portion 13 of the lid 6 is recessed downward to form a stepped shape, the stepped portion can be formed without adding another member.

In the above, the case where the height is the smallest among the plurality of electronic components 3 to 5 and the electronic component 3 mounted on the center side in the plane direction is the target of heat dissipation has been illustrated. The number and mounting location may be in any form. That is, the shape of the upper surface portion 13 of the lid 6 may have a step depending on the number of electronic components to be dissipated and the mounting location.

As shown in FIG. 3, if the electronic component 3 mounted on the center side and the electronic component 5 mounted on the end side in the plane direction are to be dissipated, a third is placed between the electronic component 3 and the lid 6. The configuration may be such that the first heat radiating member 16 is provided and the first heat radiating member 16 is also provided between the electronic component 5 and the lid 6. In this case, on the upper surface portion 13, the thickness of the first heat radiating member 16 provided between the electronic component 3 and the lid 6 and the thickness of the first heat radiating member 16 provided between the electronic component 5 and the lid 6 are different. Any shape may be used as long as it has steps that are equal to each other. The thickness of the first heat radiating member 16 provided between the electronic component 3 and the lid 6 is equal to the thickness of the first heat radiating member 16 provided between the electronic component 5 and the lid 6, so that the first heat radiating member is equal. It is possible to avoid the occurrence of variation in the thickness of 16 and more appropriately avoid the deterioration of heat dissipation. In this case, the thickness of the first heat radiating member 16 provided between the electronic component 3 and the lid 6 is equal to the thickness of the first heat radiating member 16 provided between the electronic component 5 and the lid 6. It means not only when are not exactly equal, but also when they are not exactly equal and there is a slight difference. The same applies to the following.

As shown in FIG. 4, the electronic component 3 mounted on the center side and the electronic component 5 mounted on the end side in the plane direction are the heat dissipation targets, and the height of the electronic component 5 is the height of the electronic component 3. If it is lower than that, in the upper surface portion 13, the portion corresponding directly above the electronic component 5 is recessed downward, so that the lower portion 13a corresponding directly above the electronic component 5 and the portion directly above the

electronic components

3 and 4 correspond to each other. Any shape may be used as long as it has an upper portion 13b. Also in this case, on the upper surface portion 13, the thickness of the first heat radiating member 16 provided between the electronic component 3 and the lid 6 and the thickness of the first heat radiating member 16 provided between the electronic component 5 and the lid 6 Any shape may be used as long as it has a step so that the two are equal to each other.

As shown in FIGS. 5 and 6, there may be a plurality of downwardly recessed portions on the upper surface portion 13. That is, if the

electronic components

3 and 5 are subject to heat dissipation and the height of the electronic component 4 that is not subject to heat dissipation is the maximum, the upper surface portion 13 corresponds to the portion directly above the electronic component 3 and the portion directly above the electronic component 5. If the shape has a first lower stage portion 13c corresponding to directly above the electronic component 3 and a second lower stage portion 13d corresponding to directly above the electronic component 5 because the two portions with the portion to be formed are recessed downward. good. By forming the upper surface portion 13 of the lid 6 to have a plurality of steps, it is possible to appropriately deal with a plurality of electronic components to be radiated.

(Second Embodiment)
The second embodiment will be described with reference to FIGS. 7 to 10. In the second embodiment, the configuration of the upper surface portion of the lid is different from that of the first embodiment described above. The electronic device 31 differs from the electronic device 1 described in the first embodiment only in the lid, and other parts are the same as those of the electronic device 1. In the electronic device 31, the lid 32 has a concave shape having a hollow portion 35 formed from the upper surface portion 33 and the side surface portion 34. The upper surface portion 33 has a lower portion corresponding to directly above the electronic component 3 because the protrusion member 36 is joined to the lower side of the portion corresponding to the portion directly above the electronic component 3 having a height lower than that of the

electronic components

4 and 5. It has a shape having 33a and an upper stage portion 33b corresponding to directly above the

electronic components

4 and 5, and has a stepped shape. That is, the protrusion member 36 is integrated with the lid 32 here, which is joined to the upper surface portion 33. The protrusion member 36 is made of the same material as the lid 32, and is made of a metal material such as aluminum or copper.

In the above configuration, since the upper surface portion 33 of the lid 32 has a stepped shape, the electronic components 3 and the lid 6 have the largest calorific value among the electronic components 3 to 5, as in the first embodiment. The distance from the upper surface portion 33 is narrowed, and the thickness of the first heat radiating member 16 between the electronic component 3 and the lid 32 is suppressed.

According to the second embodiment, the same effect as that of the first embodiment can be obtained. That is, since the lid 32 is grounded to the printed circuit board 2 in the electronic device 21, even if a noise current is induced in the lid 32 by the electromagnetic waves radiated from the electronic components 3 to 5, the induced noise is generated. Radiation noise can be suppressed by discharging the current to the grounded portion. Since the upper surface 33 of the lid 32 has a stepped shape, even if the height of the electronic component 3 to be dissipated is lower than that of the other

electronic components

4 and 5, the electronic component 3 to be dissipated and the lid 32 are still in contact with each other. By forming a step so as to narrow the distance, the thickness of the first heat radiating member 16 can be suppressed, and deterioration of heat radiating property can be avoided in advance. As a result, in a configuration in which a plurality of electronic components 3 to 5 having different heights are mounted on the printed circuit board 2, radiation noise from the plurality of electronic components 3 to 5 is appropriately suppressed and heat dissipation is appropriately improved. Can be made to. In this case, since the protrusion member 36 is joined to form a shape having a step, the step can be formed without denting a part of the upper surface portion 33 of the lid 32. If a part of the upper surface portion 33 of the lid 32 is recessed, stress may be generated at the boundary portion of the step, but such stress is generated by leaving the upper surface portion 33 of the lid 32 flat. It is possible to avoid the risk of this.

Also in this case, the upper surface 33 of the lid 32 may have a stepped shape depending on the number of electronic components to be dissipated and the mounting location. As shown in FIG. 8, if the electronic component 3 mounted on the center side and the electronic component 5 mounted on the end side in the plane direction are the heat dissipation targets, the electronic component 3 and the lid 32 are located between the electronic component 3 and the lid 32. The configuration may be such that the first heat radiating member 16 is provided and the first heat radiating member 16 is also provided between the electronic component 5 and the lid 32. In this case, on the upper surface portion 33, the thickness of the first heat radiating member 16 provided between the electronic component 3 and the protrusion 36 and the thickness of the first heat radiating member 16 provided between the electronic component 5 and the lid 32. Any shape may be used as long as it has a step so that the two are equal to each other.

As shown in FIG. 9, the electronic component 3 mounted on the center side and the electronic component 5 mounted on the end side in the plane direction are heat dissipation targets, and the height of the electronic component 5 is the height of the electronic component 3. If it is lower than that, in the upper surface portion 33, the protrusion member 36 is joined to the lower side of the portion corresponding directly above the electronic component 5, so that the lower portion 33a corresponding directly above the electronic component 5 and the electronic component 3 are joined. , 4 may have a shape having an upper portion 33b corresponding to directly above. Also in this case, on the upper surface portion 33, the thickness of the first heat radiating member 16 provided between the electronic component 3 and the lid 32 and the thickness of the first heat radiating member 16 provided between the electronic component 5 and the lid 32. Any shape may be used as long as it has a step so that the two are equal to each other.

As shown in FIG. 10, there may be a plurality of locations where the protrusion members 36 are joined to the lower side of the upper surface portion 33. That is, if the

electronic components

3 and 5 are subject to heat dissipation and the height of the electronic component 4 that is not subject to heat dissipation is the maximum, the upper surface portion 33 corresponds to the portion directly above the electronic component 3 and the portion directly above the electronic component 5. By joining the protrusion members 36 to the lower side of the two parts, the first lower stage portion 33c corresponding to directly above the electronic component 3 and the second lower stage portion 33d corresponding to directly above the electronic component 5 Any shape may be used.

(Third Embodiment)
The third embodiment will be described with reference to FIGS. 11 to 13. FIG. 12 shows a cross-sectional plane along the X1-X2 direction in FIG. The third embodiment is the first embodiment described above in that the conduction electrode is exposed on the back surface of the electronic component having the maximum height among the plurality of electronic components mounted on the printed circuit board 2. Different from. The electronic device 41 has a different configuration of electronic components from the electronic device 1 described with reference to FIGS. 1 and 2 of the first embodiment, and other parts are the same as those of the electronic device 1. In the electronic device 41, the electronic component 42 is mounted on the printed circuit board 2 in addition to the plurality of electronic components 3 to 5. The electronic component 42 is, for example, a chip capacitor, and the conduction electrode 43 is exposed on the back surface portion, which is the upper surface portion thereof. An insulating member 44 is provided between the electronic component 42 and the lid 6. In a configuration in which the conductive electrode 43 is exposed on the back surface of the electronic component 42, if the distance between the conductive electrode 43 and the lid 6 is short, a short circuit may occur between the conductive electrode 43 and the lid 6. On the other hand, in the present embodiment, the insulating member 44 is provided between the electronic component 42 and the lid 6 to prevent the occurrence of a short circuit.

According to the third embodiment, radiation noise from a plurality of electronic components 3 to 5, 42 can be appropriately suppressed, heat dissipation can be appropriately improved, and short circuit can be avoided in advance. .. The same applies to the other configurations described in the first embodiment, and as shown in FIG. 13, the same applies to the configuration in which the electronic component 42 is added to the configurations described in, for example, FIGS. 5 and 6 of the first embodiment. Is.

(Fourth Embodiment)
The fourth embodiment will be described with reference to FIGS. 14 to 15. The fourth embodiment is the second embodiment described above in that the conduction electrode is exposed on the back surface of the electronic component having the maximum height among the plurality of electronic components mounted on the printed circuit board 2. Different from. The electronic device 51 has a different electronic component configuration from the electronic device 31 described with reference to FIG. 7 of the second embodiment, and other parts are the same as the electronic device 31. In the electronic device 51, the electronic component 42 is mounted on the printed circuit board 2 in addition to the plurality of electronic components 3 to 5. Also in this case, the insulating member 44 is provided between the electronic component 42 and the lid 6.

According to the fourth embodiment, radiation noise from a plurality of electronic components 3 to 5, 42 can be appropriately suppressed, heat dissipation can be appropriately improved, and short circuit can be avoided in advance. .. The same applies to the other configurations described in the second embodiment, and as shown in FIG. 15, the same applies to the configuration in which the electronic component 42 is added to, for example, the configuration described in FIG. 10 of the second embodiment.

(Fifth Embodiment)
A fifth embodiment will be described with reference to FIGS. 16 to 17. FIG. 17 shows a cross-sectional plane along the X1-X2 direction in FIG. The fifth embodiment is the same as the first embodiment described above in that the second printed circuit board is mounted on the first printed circuit board and the same configuration as that of the first embodiment described above is mounted on the second printed circuit board. different. The first printed circuit board functions as a mother board, and the second printed circuit board functions as a module board.

The electronic device 61 includes a flat plate-shaped first printed circuit board 62 and a flat plate-shaped second printed circuit board 63 mounted on the first printed circuit board 62. The second printed circuit board 63 is equivalent to the printed circuit board 2 described in the first embodiment, and the electronic components 3 to 5, the lid 6, the heat sink 7, and the second printed circuit board 63 described in the first embodiment are placed on the second printed circuit board 63. The first heat radiating member 16 and the second heat radiating member 19 and the like are mounted. The lid 6 is physically connected to and grounded to the second printed circuit board 63. Further, the second printed circuit board 63 is electrically and physically connected to the first printed circuit board 62 via the solder bumps 64. The heat sink 7 is fixed to the first printed circuit board 62 by the fastening member 20.

According to the fifth embodiment, in the electronic device 61, the second printed circuit board 63 is mounted on the first printed circuit board 62, and the lid 6 is physically connected to the second printed circuit board 63 and grounded. Even in this configuration, the same effect as that of the first embodiment can be obtained. The same applies to the configurations in which the other configurations described in the first embodiment and the configurations described in the second embodiment are mounted on the second printed circuit board 63.

(Sixth Embodiment)
The sixth embodiment will be described with reference to FIGS. 18 to 19. FIG. 19 shows a cross-sectional plane along the X1-X2 direction in FIG. The sixth embodiment is different from the fifth embodiment described above in that the lid is grounded to the first printed circuit board. The electronic device 71 includes a flat plate-shaped first printed circuit board 72 and a flat plate-shaped second printed circuit board 73 mounted on the first printed circuit board 72. The second printed circuit board 73 is equivalent to the printed circuit board 63 described in the fifth embodiment except that the lid is not physically connected and is not grounded, and the second printed circuit board 73 is on the second printed circuit board 73. The electronic components 3 to 5, the lid 6, the heat sink 7, the first heat radiating member 16, the second heat radiating member 19, and the like described in the first embodiment are mounted. The lid 6 is physically connected to and grounded to the first printed circuit board 72. Further, the second printed circuit board 73 is electrically and physically connected to the first printed circuit board 72 via the solder bumps 74. The heat sink 7 is fixed to the first printed circuit board 72 by the fastening member 20.

According to the sixth embodiment, in the electronic device 71, the second printed circuit board 73 is mounted on the first printed circuit board 72, and the lid 6 is physically connected to the first printed circuit board 72 and grounded. Even in this configuration, the same effect as that of the first embodiment can be obtained. The same applies to the configurations in which the other configurations described in the first embodiment and the configurations described in the second embodiment are mounted on the second printed circuit board 73.

(Other embodiments)
The present disclosure has been described in accordance with the examples, but it is understood that the present disclosure is not limited to the examples and structures. The present disclosure also includes various modifications and modifications within a uniform range. In addition, various combinations and forms, as well as other combinations and forms containing only one element, more or less, are also within the scope of the present disclosure.

In the first to fourth embodiments, the number and arrangement of electronic components mounted on the printed circuit board 2 may be other than those illustrated. In the fifth to sixth embodiments, the number and arrangement of the second printed

circuit boards

63 and 73 mounted on the first printed

circuit boards

62 and 72, and the electronic components mounted on the second printed

circuit boards

63 and 73. The number and arrangement modes of the above may be other than those illustrated. In the sixth embodiment, one lid may cover the plurality of second printed

circuit boards

63, 73.

On the upper surfaces of the

lids

6 and 32, there are a configuration in which a portion corresponding directly above the electronic component to be dissipated is recessed downward and a configuration in which a protrusion member is provided on the lower side of the portion corresponding directly above the electronic component to be dissipated. It may coexist.

When the heights of a plurality of electronic components to be radiated are equal and the electronic components to be radiated having the same height are provided adjacent to each other, the plurality of heat radiating targets are provided on the upper surfaces of the

lids

6 and 32. The shape may have a lower portion in common with the electronic components of the above.

Although the configuration in which the

lids

6 and 32 are grounded to the printed circuit boards 2 and the second printed

circuit boards

62 and 72 by solder bonding is illustrated, the

lids

6 and 32 are conductive adhesives to the printed

circuit boards

2, 62 and 72. It may be grounded by the above, or it may be grounded by using the pressing force when the heat sink 72 is fastened to the printed

circuit boards

2, 62, 72.

Claims

Printed circuit board (2) and
A plurality of electronic components (3 to 5) mounted on the printed circuit board and having different heights.
A lid (6,32) made of a metal material, which covers the plurality of electronic components and is grounded to the printed circuit board.
A first heat radiating member (16) provided between at least one or more heat radiating electronic components among the plurality of electronic components and the lid, and
A heat sink (7) provided above the lid and
A second heat radiating member (19) provided between the lid and the heat sink is provided.
The upper surface of the lid is an electronic device (1,31,41,51) having a shape having a step according to the height of the plurality of electronic components.
With the first printed circuit board (62)
The second printed circuit board (63) mounted on the first printed circuit board and
A plurality of electronic components (3 to 5) mounted on the second printed circuit board and having different heights.
A lid (6, 32) made of a metal material, which covers the plurality of electronic components and is grounded to the second printed circuit board.
A first heat radiating member (16) provided between at least one or more heat radiating electronic components among the plurality of electronic components and the lid, and
A heat sink (7) provided above the lid and
A second heat radiating member (19) provided between the lid and the heat sink is provided.
The upper surface of the lid is an electronic device (61) having a shape having a step according to the height of the plurality of electronic components.
With the first printed circuit board (72)
The second printed circuit board (73) mounted on the first printed circuit board and
A plurality of electronic components (3 to 5) mounted on the second printed circuit board and having different heights.
A lid (6, 32) made of a metal material, which covers the plurality of electronic components and is grounded to the first printed circuit board.
A first heat radiating member (16) provided between at least one or more heat radiating electronic components among the plurality of electronic components and the lid, and
A heat sink (7) provided above the lid and
A second heat radiating member (19) provided between the lid and the heat sink is provided.
The upper surface of the lid is an electronic device (71) having a shape having a step according to the height of the plurality of electronic components.
The electronic device according to any one of claims 1 to 3, wherein the upper surface portion of the lid has a shape having a step due to a portion corresponding to directly above the electronic component to be dissipated being recessed downward.
The upper surface of the lid has a shape having a step by providing a protrusion member on the lower side of a portion directly above the electronic component to be dissipated, according to any one of claims 1 to 3. The described electronic device.
A plurality of electronic components having different heights are the electronic components to be dissipated.
The electronic device according to any one of claims 1 to 5, wherein the upper surface portion of the lid has a shape having a plurality of steps according to the heights of the plurality of electronic components to be radiated.
A plurality of electronic components having different heights are the electronic components to be dissipated.
The electronic device according to any one of claims 1 to 6, wherein the plurality of first heat radiating members corresponding to the plurality of electronic components to be radiated have the same thickness.
The plurality of electronic components include an electronic component (42) whose conduction electrode is exposed on the back surface thereof.
The electronic device according to any one of claims 1 to 7, further comprising an insulating member (44) provided between the lid and the conduction electrode.