JP2018142565A - Electronic control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic control device capable of suppressing the amount of distortion that is generated in a metal connection material of an electronic component lead part, while securing a heat dissipation performance.SOLUTION: The present invention relates to an electronic control device characterized in that, as a distortion suppression mechanism, an electronic component 4 and a circuit board 3 are connected via a metal connection material not only between an electronic component lead part 41 and the circuit board but also between a metal member 43 which is exposed at the side of the circuit board and included in the electronic component, and the circuit board. A heat dissipation member 7 is installed in an opening 5, and the heat dissipation member is brought into contact with the electronic component and a housing.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electronic control device such as an engine control unit and an automatic transmission control unit, and more particularly to a heat dissipation structure for electronic components.

  Electronic control devices such as engine control units and automatic transmission control units mounted in vehicles such as vehicle interiors and engine rooms are circuit boards mounted with electronic components, connectors and circuits mounted on circuit boards and connected to external connectors. It is comprised by the housing | casing which accommodates a board | substrate, the sealing member etc. which ensure the airtightness in a housing | casing. As a structure for releasing heat generated from an electronic component to the outside, for example, in Patent Document 1, an opening is provided in a circuit board on which the electronic component is mounted, the circuit board facing the electronic component package part, and Has a structure in which a protrusion is provided toward the opening, and a heat radiating member is installed in the opening so as to be in contact with the electronic component and the protrusion.

JP 2006-294754 A

  However, in the structure described above, the electronic component lead portion and the circuit board are connected via a metal connection material such as solder, while the electronic component package portion is connected to the housing via a heat dissipation member. Since the heat dissipation member has a large coefficient of linear expansion with respect to the metal connecting material, a displacement amount due to a heat change is large, and a large strain is generated in the metal connecting material. The strain is a cause of a crack generated in the metal connection material, and depending on the progress of the crack, the electrical connection between the electronic component and the circuit board is lost, which leads to a malfunction of the electronic control device. A structure that suppresses the distortion is required.

  The present invention provides an electronic component, a circuit board on which the electronic component is mounted, a connector that is mounted on the circuit board and is connected to an external connector, a housing that houses the circuit board, and is installed between the electronic component and the housing. In an electronic control device comprising a heat dissipating member, the connection of the electronic component and the circuit board via the metal connection material is performed not only between the electronic component lead part and the circuit board but also the circuit of the electronic component. The metal member exposed on the substrate side and the circuit board are also connected via at least one metal connection material, and an opening is provided in the circuit board facing the metal member, and the opening The electronic control device is characterized in that a heat radiating member is installed in the portion, and the heat radiating member is in contact with the electronic component and the housing.

  ADVANTAGE OF THE INVENTION According to this invention, the distortion amount which generate | occur | produces in the metal connection material of an electronic component lead part can be suppressed, ensuring heat dissipation performance. Structures and problems other than those described above will be clarified by the following description of embodiments.

It is sectional drawing which shows the thermal radiation structure of the electronic control apparatus of 1st embodiment of this invention. It is a perspective view which shows the thermal radiation structure of the electronic control apparatus of 2nd embodiment of this invention. It is a perspective view which shows the thermal radiation structure of the electronic control apparatus of 3rd embodiment of this invention. It is a perspective view which shows the thermal radiation structure of the electronic control apparatus of 4th embodiment of this invention. It is a perspective view which shows the thermal radiation structure of the electronic controller of 5th embodiment of this invention. It is a perspective view which shows the thermal radiation structure of the electronic control apparatus of the 6th embodiment of this invention. It is sectional drawing which shows the thermal radiation structure of the electronic control apparatus of the 7th embodiment of this invention. It is sectional drawing which shows the thermal radiation structure of the electronic control apparatus of 8th embodiment of this invention.

  Hereinafter, each embodiment of the thermal radiation structure concerning the present invention is explained in full detail based on a drawing.

[First embodiment]
FIG. 1 is a cross-sectional view showing the heat dissipation structure of the first embodiment of the present invention. The electronic component 4 is mounted on the circuit board 3. The cover 1 and the base 2 form a housing that includes the electronic component 4 and the circuit board 3. The base 2 and the cover 1 serve to protect the electronic component 4 and the circuit board 3 from the external environment. The base 2 is desirably a member that promotes heat dissipation caused by the heat generated by the electronic component 4, and is preferably formed of a metal material such as aluminum. The electronic component 4 has a bare chip 42 mounted therein, and is electrically connected to the lead portion 41 through wire bonding, which is abbreviated. Although the bare chip 42 is abbreviated, it is connected to the metal member 43 with an adhesive having a heat dissipation property.

  The bare chip 42, the wire bonding, the adhesive, a part of the lead part 41, and a part of the metal member 43 are sealed with a resin 40. The circuit board 3 has an opening 5 so as to face the metal member 43. The base 2 includes a protrusion 20 that faces the metal member 43 and is close to the metal member 43 with a predetermined clearance inside the opening 5.

  The protrusion 20 and the metal member 43 are in contact with each other by the heat radiating member 7, and the heat generated from the bare chip 42 is transferred to the base 2 through the metal member 43, the heat radiating member 7, and the protrusion 20, Dissipate heat to the environment. Various shapes are conceivable for the shape of the opening 5 and the protruding portion 20 without departing from the spirit thereof, and examples thereof include a circle and a quadrangle. Further, the protrusion 20 does not necessarily have a shape similar to that of the opening 5. For example, when the opening 5 is circular, the protrusion 20 may be a quadrangle.

  A part of the lead part 41 and a part of the metal member 43 are exposed, the exposed part of the lead part 41 via the metal connection material A60, and the exposed part of the metal member 43 via the metal connection material B61. Each is electrically connected to the circuit board 3. As the material of the lead portion 41 and the metal member 43, for example, a copper alloy having a high thermal conductivity is conceivable, and a plating process may be performed for the purpose of ensuring good adhesion to the metal connecting material. It is done. As the metal connection material, for example, a solder material, a silver paste, or the like can be considered.

  The electronic component 4 is in contact with the circuit board 3 via the metal connection material and the base 2 via the heat dissipation member 7. The heat dissipation member 7 has a larger coefficient of linear expansion than the metal connection material, in other words, the displacement due to temperature change is large. In particular, since the metal connection material A60 electrically connects each lead portion of the electronic component 4 and the circuit board 3, when the metal connection material A60 is disconnected due to the generated strain, the electrical connection is lost, and as a result, electronic control is performed. It leads to malfunction of the device. By providing the metal connection material B61, the strain amount can be dispersed, in other words, the strain generated in the metal connection material A60 can be reduced. Although the metal connecting material B61 plays a role of connecting the heat dissipation member 7 and the circuit board 3, even if a large distortion occurs in the metal connecting material B61 and the metal connecting material B61 is disconnected, the metal member 43 is at the ground. Therefore, there is no influence due to the loss of the electrical connection between the metal member 43 and the circuit board 3.

  Further, the metal connection material A60 and the metal connection material B61 may be the same material or different materials. For example, only the metal connection material A60 that connects the electronic component lead part 41 and the circuit board 3 may be a metal material that is less prone to crack propagation.

  According to the present embodiment, the metal member 43 on which the bare chip 42 is mounted is in contact with the base 2 via the heat radiating member 7. That is, since heat can be transferred to the base 2 without passing through a through hole or the like as a thermal path, heat dissipation is excellent. And durability with respect to distortion of metal connection material A60 can be improved by connecting metal member 43 and substrate 3 with metal connection material B61. Therefore, there is an effect that it is possible to achieve both improvement in heat dissipation and improvement in reliability.

[Second Embodiment]
FIG. 2 is a perspective view showing a heat dissipation structure of the second embodiment of the present invention. In addition, the one part component of the electronic component 4 is abbreviate | omitted, and description of the structure similar to 1st embodiment is abbreviate | omitted.

  In this structure, a metal connection material B61 is provided on the entire outer edge of the opening 5. Although the metal connection material B61 is abbreviated, the metal member 7 of the electronic component 4 and the circuit board 3 are electrically connected. By connecting the electronic component 4 and the circuit board 3 via the metal connection material A60 and the metal connection material B61, it is possible to disperse the distortion generated in the metal connection material due to thermal deformation and vibration, in other words. For example, the amount of distortion generated in the metal connection material A60 that electrically connects the lead portion 41 and the circuit board 3 can be reduced. By providing the metal connection material B61 on the entire outer periphery of the opening 5 and connecting it over a wide area, the reduction allowance becomes larger.

[Third embodiment]
FIG. 3 is a perspective view showing a heat dissipation structure of the third embodiment of the present invention. In addition, the one part component of the electronic component 4 is abbreviate | omitted, and description of the structure similar to 1st embodiment is abbreviate | omitted.

  FIG. 3 shows a structure in which four metal connection materials B61 are provided at the four corners of the outer edge of the opening 5. By reducing the amount of the metal connection material B61, it is possible to prevent the influence of the heat shrinkage of the metal connection material B61 itself from being transmitted to the electronic component 4. Moreover, since the metal connection material B61 is provided in the four corner directions where the metal connection material A60 is not provided, the connection reliability of the electronic component 4 can be improved efficiently. About metal connection material B61, various shapes, positions, and the number of positions can be considered in the range which does not deviate from the meaning.

[Fourth embodiment]
FIG. 4 is a perspective view showing a heat dissipation structure of the fourth embodiment of the present invention. In addition, the one part component of the electronic component 4 is abbreviate | omitted, and description of the structure similar to 3rd embodiment is abbreviate | omitted.

  FIG. 4 shows a structure in which six metal connection materials B61 are provided. About metal connection material B61, various shapes, positions, and the number of installations can be considered in the range which does not deviate from the meaning. According to this embodiment, the connection reliability of the electronic component 4 can be further improved.

[Fifth embodiment]
FIG. 5 is a perspective view showing a heat dissipation structure of the fifth embodiment of the present invention. In addition, the one part component of the electronic component 4 is abbreviate | omitted, and description of the structure similar to 3rd embodiment is abbreviate | omitted.

  The metal connection material B61 is disposed in the vicinity of the end lead portion 44 and has a substantially L shape. The metal connection material A60 that electrically connects the lead portion 41 and the circuit board 3 is distorted due to thermal deformation, vibration, and the like, but particularly, the end lead portion 44 is greatly distorted. By providing the metal connecting material B61 for electrically connecting the metal member 7 of the electronic component 4 and the circuit board 3 in the vicinity of each end lead portion 44, distortion generated in each end lead portion 44 can be reduced.

[Sixth embodiment]
FIG. 6 is a perspective view showing a heat dissipation structure of the sixth embodiment of the present invention. In addition, the one part component of the electronic component 4 is abbreviate | omitted, and description of the structure similar to 5th embodiment is abbreviate | omitted.

  FIG. 6 shows a structure in which the metal connection material B61 is made larger than the other lead portion 44 only in the vicinity of the end lead portion A45 where the maximum strain occurs.

[Seventh embodiment]
FIG. 7 is a cross-sectional view showing the heat dissipation structure of the seventh embodiment of the present invention. In addition, description is abbreviate | omitted about the structure similar to 1st embodiment.

  In the present embodiment, the heat radiation via 50 of a minute through hole extending in the board thickness direction from the installation surface of the metal connection material B61 and the circuit board 3 is in contact with the base 2 via the heat radiation member 7. It is a structure to do. The heat generated from the bare chip 42 is transmitted to the metal member 43 and is radiated to the base 2 through the heat radiating member 7, and the metal connection material B 61, the heat radiating via 50, and the heat radiating member 7 that are in contact with the metal member 43. Therefore, it is possible to radiate heat to the base 2, which leads to improvement in heat dissipation performance. A plurality of heat dissipation vias 50 may be provided. Further, the inside of the heat dissipation via 50 may be filled with a metal connection material or may be filled with a heat dissipation member 7.

  Further, the heat dissipation via 50 does not necessarily need to be in contact with the metal connection material B61, and may be disposed in the vicinity of the metal connection material B61.

[Eighth embodiment]
FIG. 8 is a sectional view showing the heat dissipation structure of the eighth embodiment of the present invention. In addition, description is abbreviate | omitted about the structure similar to 1st embodiment.

  In the present embodiment, the circuit board 3, the electronic component 4, and the heat dissipation member 7 included in the cover 1 and the base 2 are sealed with a sealing material 70. By sealing the circuit board 3 and the electronic component 4, it is possible to suppress deformation due to heat, vibration, or the like, and to further reduce distortion generated in the metal connection material A60. As the material of the sealing material 70, various materials such as acrylic, epoxy, and unsaturated polyester can be considered. In order to increase the thermal conductivity of the sealing material 70, a heat radiation filler may be included. Various materials such as silica, aluminum oxide, zinc oxide, boron nitride are conceivable as the material of the heat dissipating filler.

  Further, the heat radiating member 7 shown in FIG. 8 is not necessary, and the space between the metal member 43 of the electronic component 4 and the protruding portion 20 located in the opening 5 may be filled with the sealing material 70.

  In addition, this invention is not limited to above-described embodiment, Various modifications are included. For example, the above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to the one having all the configurations described. In addition, a part of the configuration of an embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of an embodiment. In addition, it is possible to add, delete, and replace other configurations for a part of the configurations of the other embodiments. For example, various shapes including the internal structure can be adopted as the electronic component shape.

1: Cover 2: Base 3: Circuit board 4: Electronic component 5: Opening 7: Heat radiation member 20: Projection 40: Resin 41: Lead
42: Bare chip 43: Metal member
44: End lead portion 45: End lead portion A
50: Heat dissipation via 60: Metal connection material A
61: Metal connecting material B
70: Sealing material

Claims (7)

An electronic control device mounted on an automobile includes an electronic component, a circuit board on which the electronic component is mounted, and a housing that encloses the electronic component and the circuit board.
The housing includes a base and a cover, and the electronic component is
A metal member for mounting a semiconductor chip; a lead for inputting and outputting signals of the semiconductor chip; and a resin for sealing so as to expose a part of the metal member and the lead portion;
The circuit board includes an opening,
The base has a protrusion inserted into the hole;
The protrusion and the metal member are in contact via a heat dissipation member,
The electronic control device in which the metal member is connected to the circuit board by a metal connecting material.   2. The electronic control unit according to claim 1, wherein the metal connection material that connects the lead of the electronic component and the circuit board is the same material as the metal connection material that connects the metal member and the circuit board.   The electronic control device according to claim 1, wherein a metal connection material that connects the metal member and the circuit board is in the vicinity of an end of the electronic component. The opening is a square shape having a corner,
3. The electronic control device according to claim 1, wherein a metal connection material that connects the metal member and the circuit board is provided in the vicinity of a corner of the opening.   The circuit board has a through hole in which a metal plating is applied to an inner wall of a minute through hole, and the metal member and the through hole are connected by a metal connecting material that connects the metal member and the circuit board. The electronic control device according to claim 1, wherein the hole is in contact with the base via the heat radiating member.   The electronic control device according to claim 1, wherein the inside of the housing is sealed with a sealing resin.   The electronic control device according to claim 1, wherein the sealing resin also serves as a heat dissipation member.

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