JP2017162860A - Electronic control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic control device which enables improvement of connection reliability between an electronic component and a substrate.SOLUTION: An electronic control device includes: a circuit board 3 (a substrate); a BGA 7 (a ball grid array) serving as an electronic component; a cover 2 serving as a housing; and a heat conduction material 8. The BGA 7 has an array of solder balls 9 electrically connected with the circuit board 3. The cover 2 has a heat radiation pedestal 2a facing the BGA 7. The heat conduction material 8 is disposed between the BGA 7 and the heat radiation pedestal 2a, but is not disposed on one surface S1C of a heat radiation pedestal 2a side surface S1 of the BGA 7.SELECTED DRAWING: Figure 4B

Description

  The present invention relates to an electronic control device.

  In electronic control devices mounted on vehicles such as engine control units and automatic transmission control units, the internal temperature of the housing rises due to heat generated by electronic components, causing abnormal circuit operation or damage to electronic components. Sometimes.

  For this reason, there is a heat dissipation structure that transfers heat generated by these electronic components to the housing of the apparatus and releases the heat from the surface of the housing to the outside of the housing. Specifically, a heat conductive material is interposed between the electronic component mounted on the board and the heat radiating pedestal provided in the case, and heat generated from the electronic component is transferred to the case via the heat conductive material. And is radiated from the surface of the casing to the outside of the casing.

  As a heat conductive material, for example, heat radiation grease is known (see, for example, Patent Documents 1 and 2).

  In Patent Document 1, heat dissipation grease is used as the heat conductive material, and the heat conductive material is interposed between the electronic component mounted on the circuit board and the housing, and the heat generated from the electronic component is The heat is transmitted to the housing through the heat conductive material, and is radiated from the surface of the housing to the outside of the housing.

  Moreover, in patent document 2, in the vehicle-mounted electronic control apparatus which has the structure where the circuit board electrically joined with the connector is fixed to a case, and is sealed with a cover with a waterproof seal, from the IC mounted on the board The heat dissipation structure directly conducts heat to the metal cover or case via the heat dissipation grease and dissipates heat to the air.

JP 2014-187063 A JP 2014-75496 A

  When the heat conductive material as disclosed in Patent Documents 1 and 2 is used for a BGA package (electronic component), the heat conductive material directly touches the BGA package, so that the influence of thermal deformation or external force on the housing is affected by the solder ball. The solder ball connection life is reduced.

  As a result, there is a concern that the connection reliability between the electronic component and the circuit board (substrate) is lowered.

  An object of the present invention is to provide an electronic control device capable of improving the connection reliability between an electronic component and a board.

  In order to achieve the above object, the present invention provides a substrate, an electronic component having an array of solder balls electrically connected to the substrate, a housing having a heat dissipation base facing the electronic component, and the electronic A heat conductive material disposed between the component and the heat dissipation pedestal, and the heat conductive material is not disposed in at least one corner of the first surface of the electronic component on the heat dissipation pedestal side.

  According to the present invention, the connection reliability between the electronic component and the board can be improved. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

It is a perspective view which shows the electronic controller which is a comparative example with 1st-4th embodiment. It is a disassembled perspective view which shows the electronic controller of FIG. It is a figure for demonstrating the shape of the thermal radiation base of FIG. It is sectional drawing by the AA cross section shown to FIG. 3A. It is an enlarged view of a portion B shown in FIG. 3A. It is a figure for demonstrating the shape of the thermal radiation base of the electronic control apparatus by the 1st Embodiment of this invention. It is sectional drawing by the AA cross section shown to FIG. 4A. It is the enlarged view of the part B shown to FIG. 4A. It is a figure for demonstrating the shape of the thermal radiation base of the electronic control apparatus by the 2nd Embodiment of this invention. It is sectional drawing by the AA cross section shown to FIG. 5A. It is an enlarged view of the part B shown to FIG. 5A. It is a figure for demonstrating the shape of the thermal radiation base of the electronic control apparatus by the 3rd Embodiment of this invention. It is sectional drawing by the AA cross section shown to FIG. 6A. It is an enlarged view of the part B shown to FIG. 6A. It is a figure for demonstrating the shape of the thermal radiation base of the electronic control apparatus by the 4th Embodiment of this invention. It is sectional drawing by the AA cross section shown to FIG. 7A. It is an enlarged view of the part B shown to FIG. 7A.

  Hereinafter, the configuration and operational effects of the electronic control device according to the first to fourth embodiments of the present invention will be described with reference to the drawings. In each figure, the same numerals indicate the same parts.

(Comparative example)
Initially, the structure of the electronic control apparatus 20 which is a comparative example with 1st-4th embodiment is demonstrated using FIGS. 1-3 (3A-3C). Note that the electronic control device 20 of this comparative example has the same configuration as the electronic control device 20 of the first to fourth embodiments, except for a heat dissipation base described later.

  FIG. 1 is a perspective view of an engine control unit of an automobile as an example of the electronic control device 20, and FIG. 2 is an exploded perspective view thereof. The electronic control unit 20 includes, for example, a substantially plate-like case 1 and a substantially box-like cover 2 that are attached to the vehicle body side, and a circuit board 3 (board) on which electronic components such as heat-generating electronic components and non-heat-generating electronic components are mounted. ). Case 1 and cover 2 constitute a case.

  As shown in FIG. 2, the circuit board 3 is electrically connected to a connector 4 connected to an external connector and the electronic component. The electronic component is, for example, a BGA 7 (Ball Grid Array). As shown in FIG. 3B, a chip 7b is mounted in a package 7a, and an interposer is mounted on the surface on which the chip 7b is mounted. A substrate 7c is mounted.

  Solder balls 9 are arranged in an array on the interposer substrate 7c. In other words, the BGA 7 (electronic component) has an array of solder balls 9 that are electrically connected to the circuit board 3 (substrate), as shown in FIG. 3B.

  As shown in FIG. 2, a heat conductive material 8 is interposed between the BGA 7 that is a heat generating electronic component and the inner surface of the cover 2. The heat conducting material 8 is interposed between the BGA 7 mounted on the lower side surface of the circuit board 3 and a heat radiating base 2 a provided on the cover 2. The cover 2 (housing) has a heat radiating base 2a that faces the BGA 7 (electronic component).

  The cover 2 is integrally formed in a substantially box shape with a metal material having excellent thermal conductivity such as aluminum. For example, cover fixing portions 2b for attaching and fixing the cover 2 are formed at the four corners of the outer peripheral edge (each side) of the substantially rectangular bottom wall 2c. The cover 2 and the case 1 are attached to the cover fixing portion 2 b by a case fixing screw 5.

  Further, the circuit board 3 is attached to the upper end surface of the board fixing base 2d erected at the peripheral edge (for example, four corners) and the center of the inner wall side of the cover 2 with a circuit board fixing screw 6, for example. . In other words, the circuit board 3 (substrate) is fixed to the substrate fixing base 2d.

  The heat conducting material 8 effectively transmits (conducts) the heat generated by the BGA 7 to the cover 2 side and releases it from the outer surface of the cover 2.

  However, it is generally known that the connection life of the solder balls 9a at the four corners is the weakest in the connection life of the solder balls 9 of the BGA 7. Therefore, in the structure (see FIGS. 3B and 3C) in which the heat conductive material 8 is arranged on the entire package 7a (see FIGS. 3B and 3C), the heat conductive material 8 exerts influence on the solder balls 9a at the four corners due to thermal deformation of the casing and external force. This will reduce the connection life.

  Further, it has been found from prior research that the connection life of the solder ball 9b closest to the substrate fixing base 2d among the solder balls 9a at the four corners of the BGA 7 is the lowest.

  Therefore, in the electronic control device 20 according to the first to fourth embodiments of the present invention, which will be described later, the thermal conductive material 8 is affected by the thermal deformation of the housing and the external force, and the solder balls 9a at the four corners and the substrate fixing base. In order to prevent the connection life from being shortened by giving to the solder ball 9b closest to 2d, the shape of the heat dissipation base 2a was changed.

(First embodiment)
FIG. 4 (4A to 4C) shows a first embodiment of the invention. When the heat dissipating base 2a is viewed from the front in the direction x in FIG. 1, the heat conduction is provided in the package 7a by providing a recess 2e on the surface on which the solder ball 9b closest to the board fixing base 2d is projected. In this structure, the influence of thermal deformation or external force of the housing due to the direct adhesion of the material 8 is not exerted on the solder ball 9b having the weakest connection life, thereby preventing a decrease in the solder connection life.

  In other words, as shown in FIGS. 4B and 4C, the heat conducting material 8 is disposed between the BGA 7 (electronic component) and the heat radiating base 2a, but the surface S1 (first surface) of the BGA 7 on the heat radiating base 2a side. ) In one corner S1C.

  In the present embodiment, the heat radiating base 2a has a recess 2e (first recess) facing one corner S1C of the surface S1 (first surface). Specifically, the recess 2e faces the corner S1C of the surface S1 closest to the substrate fixing base 2d.

  As described above, according to the present embodiment, the solder ball 9b having the shortest connection life among the solder balls 9 at the four corners is less affected by thermal deformation or external force of the housing. Connection reliability of the circuit board 3 (substrate) can be improved.

(Second Embodiment)
FIG. 5 (5A to 5C) shows a second embodiment of the invention. When the x direction in FIG. 1 is viewed from the front, the surface on which the heat conductive material 8 is applied in the heat radiating base 2a is in an area inside the surface on which the solder balls 9a at the four corners are projected. It is a feature.

  In other words, as shown in FIGS. 5B and 5C, the surface S2 (second surface) on the BGA 7 (electronic component) side of the heat radiating base 2a is replaced with the surface (third surface) on the circuit board 3 (substrate) side of the BGA 7. The figure obtained by projecting onto is located in a region S3a surrounded by the solder balls 9 arranged on the outermost periphery in the arrangement of the solder balls 9.

  The effect of thermal deformation and external force of the housing due to the direct attachment of the heat conductive material 8 to the package 7a is not exerted on the solder balls 9a at the four corners and the solder balls 9b having the weakest connection life. By reducing the influence of thermal deformation and external force of the housing, the solder connection life is prevented from being reduced.

  As described above, according to the present embodiment, the influence of thermal deformation or external force of the casing on all of the four solder balls 9 is reduced, so that the connection between the BGA 7 (electronic component) and the circuit board 3 (board) is achieved. Reliability can be improved.

(Third embodiment)
FIG. 6 (6A to 6C) shows a third embodiment of the invention. In the heat radiating base 2a, a concave shape 2f for applying the heat conducting material 8 is provided on the surface facing the BGA 7 as the electronic component, and when the x direction in FIG. A surface 2f1 on which 2f of the heat conductive material 8 is applied is in an area inside the solder balls 9a at the four corners.

  In other words, as shown in FIGS. 6B and 6C, the heat radiating base 2a has a concave shape 2f (second concave portion) facing the BGA 7 (electronic component). The figure obtained by projecting the concave shape 2f onto the surface S3 (third surface) of the BGA 7 on the circuit board 3 (substrate) side is an area surrounded by the solder balls arranged on the outermost periphery in the arrangement of the solder balls 9 It is in S3a. The heat conductive material 8 is disposed between the concave shape 2 f and the BGA 7.

  The effect of thermal deformation and external force of the housing due to the direct attachment of the heat conductive material 8 to the package 7a is not exerted on the solder balls 9a at the four corners and the solder balls 9b having the weakest connection life. By reducing the influence of thermal deformation and external force of the housing, the solder connection life is prevented from being reduced.

  Further, by applying the heat conductive material 8 to the concave shape 2f, the wall 2f2 (wall portion) of the concave shape 2f suppresses the adhesion of the heat conductive material 8 to the solder balls 9, thereby enabling soldering. This structure prevents the connection life from being reduced.

  As described above, according to the present embodiment, the influence of thermal deformation or external force of the casing on all of the four solder balls 9 is reduced, so that the connection between the BGA 7 (electronic component) and the circuit board 3 (board) is achieved. Reliability can be improved. Moreover, it can suppress that the heat conductive material 8 moves by the concave shape 2f (2nd recessed part).

(Fourth embodiment)
FIG. 7 (7A to 7C) shows a fourth embodiment of the invention. The concave shape 2f is provided with a convex shape 2f3.

  In other words, as shown in FIG. 7B, the heat dissipation pedestal 2a has a convex shape 2f3 (convex portion) facing the BGA 7 (electronic component) on the bottom surface of the concave shape 2f (second concave portion).

  Since the clearance between the heat radiating base 2a and the package 7a (electronic component package) is constant, in the third embodiment, the heat radiation efficiency may be lowered due to the provision of the concave shape 2f.

  4th Embodiment of the said invention is the structure which prevented the fall of the thermal radiation efficiency by installation of the said convex shape 2f3.

  As described above, according to the present embodiment, the influence of thermal deformation or external force of the casing on all of the four solder balls 9 is reduced, so that the connection between the BGA 7 (electronic component) and the circuit board 3 (board) is achieved. Reliability can be improved. Moreover, it can suppress that the heat conductive material 8 moves by the concave shape 2f (2nd recessed part). Furthermore, heat radiation efficiency can be ensured by the convex shape 2f3 (convex portion).

  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. Further, 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 configuration of each embodiment.

  In addition, the following aspects may be sufficient as embodiment of this invention.

  (1) In an electronic control device including a substrate on which an electronic component is disposed and a housing that houses the substrate, the housing has a heat dissipation base that protrudes facing the electronic component, and the electronic component is And electrically connected to the circuit board through a plurality of solder balls arranged in an array, and a heat conductive material is disposed between the heat radiation base and the electronic component package, and the heat conductive material The electronic control device according to claim 1, wherein in the applied heat dissipation base, a recess is provided at a position where a distance between a corner portion of the heat dissipation base and the substrate fixing base is the shortest.

  (2) In an electronic control device including a substrate on which an electronic component is disposed and a housing that accommodates the substrate, the housing includes a heat dissipation base that protrudes facing the electronic component, and the electronic component is And electrically connected to the circuit board through a plurality of solder balls arranged in an array, and a heat conductive material is disposed between the heat radiation base and the electronic component package, and the heat conductive material The electronic control device according to claim 1, wherein a surface on the heat radiation base to be applied is positioned inside the outermost solder ball.

  (3) In an electronic control device including a substrate on which an electronic component is disposed and a housing that houses the substrate, the housing has a heat dissipation base that protrudes facing the electronic component, and the electronic component is , Electrically connected to the circuit board via a plurality of solder balls arranged in an array, a heat conductive material is disposed between the heat dissipation base and the package of the electronic component, the heat dissipation base on the heat dissipation base An electronic control device comprising: a concave shape which is an application part of a heat conducting material, wherein the concave shape is located inside the outermost solder ball.

  (4) In the electronic control device according to (3), a heat conductive material is disposed between the heat dissipation pedestal and the package of the electronic component, and the heat dissipation material has a concave shape that is the heat conductive material application portion. An electronic control device, wherein the concave shape is located inside the solder ball on the outermost periphery, and a convex shape is provided in the concave shape.

  (5) The electronic control device according to any one of (1) to (4), wherein the heat conductive material is a heat conductive grease, a heat conductive adhesive, or a heat conductive sheet. .

  That is, BGA is the most soldered connection in an electronic control device that is configured to thermally connect a circuit board on which an electronic component is mounted and a housing that encloses the board using a heat conductive material having flexibility. The shape of the heat dissipating base was changed so that the four corners (corners) having a short life would not be directly affected by the heat conducting material.

DESCRIPTION OF SYMBOLS 1 ... Case 2 ... Cover 2a ... Radiation base 2b ... Cover fixing | fixed part 2c ... Cover bottom wall 2d ... Substrate fixation base 2e ... Concavity 2f provided in the radiation base 2a ... Concave shape 2f1 ... 2f provided in the radiation base 2a Surface 2f2 to which 8 is applied ... Wall 2f3 composed of concave portion 2f and heat radiation base 2a ... Convex shape 3 provided on concave shape 2f ... Circuit board 4 ... Connector 5 ... Housing fixing screw 6 ... Circuit board fixing screw 7 ... BGA
7a ... electronic component package 7b ... chip 7c ... interposer substrate 8 ... thermal conductive material 9 ... solder ball 9a ... solder ball 9b at the four corners of BGA 7 ... solder ball 20 at the four corners of BGA 7 closest to the substrate fixing base 2d ... electronic Control device

Claims (7)

A substrate,
An electronic component having an array of solder balls electrically connected to the substrate;
A housing having a heat dissipation base facing the electronic component;
A heat conductive material disposed between the electronic component and the heat dissipation base,
The heat conducting material is
An electronic control device, wherein the electronic control device is not disposed in at least one corner of the first surface of the electronic component on the heat dissipation pedestal side. The electronic control device according to claim 1,
The heat dissipation pedestal is
An electronic control device comprising a first recess facing at least one corner of the first surface. The electronic control device according to claim 2,
The housing is
A substrate fixing base to which the substrate is fixed;
The first recess is
The electronic control device, wherein the electronic control device faces a corner of the first surface closest to the substrate fixing base. The electronic control device according to claim 1,
The figure obtained by projecting the second surface of the heat dissipating pedestal on the electronic component side onto the third surface of the electronic component on the substrate side is a solder ball arranged on the outermost periphery of the array of solder balls. An electronic control device characterized by being in a region surrounded by. The electronic control device according to claim 1,
The heat dissipation pedestal is
A second recess facing the electronic component;
The figure obtained by projecting the second concave portion onto the third surface of the electronic component on the substrate side is in a region surrounded by solder balls arranged on the outermost periphery in the arrangement of the solder balls,
The thermal control material is disposed between the second recess and the electronic component. The electronic control device according to claim 5,
The heat dissipation pedestal is
An electronic control device comprising a convex portion facing the electronic component on a bottom surface of the second concave portion. The electronic control device according to claim 1,
The heat conducting material is
An electronic control device, characterized by being a heat conductive grease, a heat conductive adhesive, or a heat conductive sheet.

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