Electronic control unit

Abstract

The present invention provides an electronic control device that can reduce the load on the joint between electronic components and a substrate while ensuring proper contact between the heat conduction part and the electronic components and the heat dissipation part. [Solution] The electronic control device 1 comprises a substrate 13, electronic components 15 and 17, a heat dissipation section 21, a heat conduction section 23, and a back plate section 25. The back plate section 25 is constructed by laminating materials with different coefficients of thermal expansion so that it can deform into a shape according to the temperature, and is positioned so as to be in contact with the second surface 13B. When the temperature rises, it deforms into a shape that increases the pressing force against the second surface, and when the temperature falls, it deforms into a shape that decreases the pressing force against the second surface.

Description

Technical Field

[0001] The present disclosure relates to an electronic control device.

Background Art

[0002] For example, Patent Document 1 discloses a technique in which a heat conduction part is sandwiched between an electronic component and a heat dissipation part, and both the electronic component and the heat dissipation part are brought into pressure contact with the heat conduction part by the spring force of a back plate. The high-power processor (104) as an electronic component is mounted on a PCB (102) as a substrate. The sliding pedestal (410) as a heat dissipation part is configured to be displaceable with respect to the PCB.

[0003] The TIM layer (202) as a heat conduction part is sandwiched between the high-power processor and the sliding pedestal. The spring load back plate (416) biases the sliding pedestal toward the TIM layer side. By using such a technique, the TIM layer can be compressed between the sliding pedestal and the high-power processor, and the TIM layer can be made to adhere closely to both the sliding pedestal and the high-power processor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the technique described in Patent Document 1, the spring force from the back plate is always in a state of acting on the substrate and the electronic component. Therefore, a load is always continuously applied to the solder part that is the joint portion between the substrate and the electronic component.

[0006] In one aspect of this disclosure, it is desirable to provide an electronic control device that can reduce the load on the joint between an electronic component and a substrate while ensuring that the heat conduction part is in proper contact with the electronic component and the heat dissipation part. [Means for solving the problem]

[0007] One aspect of the present disclosure is an electronic control device (1) comprising a substrate (13), electronic components (15, 17), a heat dissipation section (21), a heat conduction section (23), and a backplate section (25). The substrate has a first surface (13A) and a second surface (13B). The electronic components are mounted on the first surface side. The heat dissipation section is positioned opposite the first surface. The heat conduction section is made of a thermal interface material and is positioned to be interposed between the electronic components and the heat dissipation section. The backplate section is constructed by laminating materials with different coefficients of thermal expansion so as to be deformable according to temperature, and is positioned so as to be in contact with the second surface, deforming to a shape that increases the pressing force against the second surface when the temperature rises and deforming to a shape that decreases the pressing force against the second surface when the temperature falls.

[0008] With the electronic control device configured in this way, the backplate deforms into a shape that increases the pressing force on the second surface when the temperature rises, and deforms into a shape that decreases the pressing force on the second surface when the temperature falls. Therefore, when the electronic control device is operating, the pressing force acting from the backplate to the substrate increases, which improves the adhesion between the heat dissipation part and the heat conduction part of the electronic component, thereby improving the heat conduction from the electronic component to the heat dissipation part. Also, when the electronic control device is stopped, the pressing force acting from the backplate to the substrate decreases, which reduces the load on the joint between the electronic component and the substrate.

[0009] One aspect of the present disclosure is an electronic control device comprising a substrate (13), electronic components (15, 17), a heat dissipation section (45), and a heat conduction section (23). The substrate has a first surface (13A) and a second surface (13B). The electronic components are mounted on the first surface side. The heat dissipation section is positioned opposite the first surface. The heat conduction section is made of a thermal interface material and is positioned between the electronic components and the heat dissipation section. The heat dissipation section is configured to be deformable according to temperature by laminating materials with different coefficients of thermal expansion, and is configured to deform to increase the pressing force on the heat conduction section when the temperature rises and to decrease the pressing force on the heat conduction section when the temperature falls.

[0010] In this electronic control unit configuration, the heat dissipation section deforms to increase the pressure on the heat conduction section when the temperature rises, and deforms to decrease the pressure on the heat conduction section when the temperature falls. Therefore, when the electronic control unit is operating, the pressure acting from the heat dissipation section to the heat conduction section increases, improving the adhesion between the heat dissipation section and the heat conduction section of the electronic components, and thus improving the heat conductivity from the electronic components to the heat dissipation section. Furthermore, when the electronic control unit is stopped, the pressure acting from the heat dissipation section to the heat conduction section decreases, reducing the load on the joint between the electronic components and the substrate. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is an explanatory diagram showing the schematic structure of the electronic control device in the first embodiment. [Figure 2] Figure 2 is an enlarged view of part II shown in Figure 1. [Figure 3] Figure 3 is an explanatory diagram showing the substrate and backplate viewed from below. [Figure 4] Figure 4 is an explanatory diagram showing the deformed state of the backplate portion. [Figure 5] Figure 5 is an enlarged view of section V shown in Figure 4. [Figure 6] Figure 6 is an explanatory diagram showing the main components of the electronic control device in the second embodiment. [Figure 7]Figure 7 is an explanatory diagram showing the substrate, backplate, and intermediate member as viewed from below. [Figure 8] Figure 8 is an explanatory diagram showing the main components of the electronic control device in the third embodiment. [Figure 9] Figure 9 is an explanatory diagram showing the substrate, backplate, and flexible member as viewed from below. [Figure 10] Figure 10 is an explanatory diagram showing the main components of the electronic control device in the fourth embodiment. [Figure 11] Figure 11 is an explanatory diagram showing an example in which the heat dissipation unit in the fourth embodiment is mounted on the inside of the housing. [Modes for carrying out the invention]

[0012] Next, the above-mentioned electronic control device will be described with reference to exemplary embodiments. (1) First Embodiment [Configuration of the electronic control unit] As shown in Figures 1 and 2, the electronic control unit 1 comprises a housing 11, a circuit board 13, an interposer 15, a chip 17, a heat dissipation section 21, a heat conduction section 23, and a backplate section 25. In this embodiment, the housing 11 is a die-cast part made of aluminum alloy. The housing 11 has an upper housing 11A and a lower housing 11B, and the lower housing 11B is attached to the upper housing 11A by a fastener 11C.

[0013] The substrate 13 is mounted inside the housing 11 by a fixing device 31. The substrate 13 has a first surface 13A and a second surface 13B. The chip 17 is mounted on the interposer 15. The interposer 15 has wiring formed therein that electrically connects the chips 17 and wiring that electrically connects the chips 17 and the substrate 13. In this embodiment, the semiconductor module composed of the interposer 15 and the chip 17 corresponds to the electronic component as referred to in this disclosure. The interposer 15 is mounted on the first surface 13A side of the substrate 13. The interposer 15 and the substrate 13 are electrically connected via solder balls 33 arranged in a grid.

[0014] In the case of this embodiment, the heat radiating part 21 is a part of the housing 11 and is integrally formed with the housing 11. A heat radiating fin 21A is provided on the outer surface side of the heat radiating part 21. The heat radiating part 21 is disposed at a position facing the first surface 13A of the substrate 13 and at a position spaced apart from the chip 17.

[0015] The heat conducting part 23 is composed of a thermal interface material with high thermal conductivity and is disposed so as to be interposed between the chip 17 and the heat radiating part 21. The thermal interface material is a soft material with high thermal conductivity. Examples of such a soft material include silicone resin, epoxy resin, acrylic resin, etc. In the case of this embodiment, the heat conducting part 23 is composed of a soft silicone resin with high thermal conductivity. These soft materials may be blended with a thermal conductivity filler composed of a material with high thermal conductivity, such as alumina particles.

[0016] The back plate part 25 is composed of a bimetal material having a first layer 25A on the substrate 13 side and a second layer 25B on the opposite side of the substrate 13 with the first layer 25A interposed therebetween. That is, the back plate part 25 is configured to be deformable into a shape according to temperature by laminating materials with different linear expansion coefficients. In the back plate part 25, the linear expansion coefficient of the material constituting the first layer 25A is configured to be larger than the linear expansion coefficient of the material constituting the second layer 25B.

[0017] As shown in FIG. 3, the back plate part 25 is configured in a rectangular frame shape, and mounting holes 35 are formed at its four corners. As shown in FIG. 2, a shaft part 37 provided on the housing 11 side is passed through the mounting holes 35, and a retaining member 39 is attached to the shaft part 37, whereby the back plate part 25 is attached to the housing 11. The back plate part 25 is disposed at a position where it can contact the second surface 13B of the substrate 13.

[0018] When the electronic control unit 1 is operating, the temperature of the backplate portion 25 rises due to the heat generated by the electronic components, etc. When the temperature of the backplate portion 25 reaches a high temperature, for example, 100°C or higher, the backplate portion 25 deforms into a shape that increases the pressing force against the second surface 13B, as shown in Figures 4 and 5. At this time, the substrate 13 bends slightly due to the pressing force from the backplate portion 25, and the bent portion is displaced in a direction that moves closer to the heat dissipation portion 21. The amount of displacement of the substrate 13 at this time is about 1 mm or less.

[0019] The interposer 15 and the chip 17 are displaced together with the substrate 13, pressing against the heat conduction section 23. As a result, the heat conduction section 23 receives a compressive load between the heat dissipation section 21 and the chip 17, and deforms in accordance with the displacement of the chip 17. Consequently, the adhesion of the heat conduction section 23 to the heat dissipation section 21 and the chip 17 is improved, and the heat conductivity from the chip 17 to the heat dissipation section 21 is improved.

[0020] When the electronic control unit 1 is stopped, the temperature of the backplate portion 25 decreases and returns to room temperature. When the temperature of the backplate portion 25 returns to room temperature, for example, to below 40°C, the backplate portion 25 deforms into a shape that reduces the pressing force against the second surface 13B, as shown in Figures 1 and 2.

[0021] In this embodiment, the backplate portion 25 moves to a position away from the second surface 13B. As a result, no pressing force is applied from the backplate portion 25 to the second surface 13B. In this state, no load is applied to the solder balls 33, and unlike structures in which pressing force is constantly applied from the backplate portion, the load on the joint between the substrate 13 and the interposer 15 can be reduced.

[0022] [effect] With the electronic control unit 1 configured as described above, the backplate portion 25 deforms according to the temperature. Therefore, when the electronic control unit 1 is operating, the thermal conductivity from the chip 17 to the heat dissipation portion 21 can be improved, and when the electronic control unit 1 is stopped, the load on the solder ball 33 can be reduced.

[0023] Furthermore, in this embodiment, the backplate portion 25 is attached to a part of the housing 11. Therefore, unlike the case where the backplate portion 25 is attached to the substrate 13, it is possible to suppress excessive warping of the substrate 13 in response to the deformation of the backplate portion 25.

[0024] Furthermore, in this embodiment, since the backplate portion 25 is formed in a frame shape, the amount of deformation of the backplate portion 25 can be easily adjusted compared to when it is formed in a planar shape. In addition, the backplate portion 25 can press against the substrate 13 at four locations on the four sides of the frame shape.

[0025] (2) Second Embodiment Next, the second embodiment will be described. Note that each embodiment from the second embodiment onward only modifies a part of the configuration exemplified in the first embodiment. Therefore, the differences from the first embodiment will be described in detail, and detailed explanations of parts similar to the first embodiment will be omitted.

[0026] In the second embodiment, as shown in Figures 6 and 7, an intermediate member 41 is provided, which is attached to the backplate portion 25 and positioned between the backplate portion 25 and the substrate 13. In this embodiment, the intermediate member 41 is a cylindrical member made of hard resin. The height of the intermediate member 41 is set considering the shape of the backplate portion 25 when its temperature rises, and is configured so that the tip of the intermediate member 41 reaches the substrate 13 when the temperature of the backplate portion 25 rises.

[0027] When the backplate portion 25 deforms, a pressing force is transmitted from the backplate portion 25 to the second surface 13B of the substrate 13 via the intermediate member 41. At that time, the intermediate member 41 transmits the pressing force to the second surface 13B at multiple points. Therefore, in the first embodiment, the backplate portion 25 pressed the second surface 13B at four contact points corresponding to each of the four sides, whereas in the second embodiment, the second surface 13B can be pressed at 16 contact points corresponding to the intermediate member 41. Thus, the points of pressure on the substrate 13 can be distributed more evenly than in the first embodiment, and the load on each pressing point can be reduced.

[0028] In this embodiment, the intermediate member 41 is described as being made of a hard resin, but the intermediate member 41 may be made of synthetic rubber or the like to create a structure that can expand and contract in the axial direction. In this case, even if the height of all the intermediate members 41 is the same, the intermediate members 41 will deform in a direction that compresses them as they come into contact with the substrate 13, so all of the intermediate members 41 can come into contact with the substrate 13.

[0029] (3) Third Embodiment Next, a third embodiment will be described. In the third embodiment, as shown in Figures 8 and 9, a flexible member 43 is provided, which is attached to the backplate portion 25 and positioned between the backplate portion 25 and the substrate 13. In this embodiment, the flexible member 43 is made of a flexible resin. When the backplate portion 25 deforms, a pressing force is transmitted from the backplate portion 25 to the second surface 13B of the substrate 13 via the flexible member 43. At that time, the flexible member 43 transmits the pressing force to the second surface 13B over the entire area spanning both ends of the flexible member 43. Therefore, in the first embodiment, the backplate portion 25 pressed the second surface 13B at four contact points corresponding to each of the four sides, whereas in the third embodiment, the second surface 13B can be pressed over a wider area. Thus, the points of pressure on the substrate 13 can be distributed more evenly than in the first embodiment, and the load on each pressing point can be reduced.

[0030] (4) Fourth Embodiment Next, a fourth embodiment will be described. In the fourth embodiment, as shown in Figure 10, the heat dissipation section 45 is configured as a separate component from the housing 11. This heat dissipation section 45 is attached to the housing 11 by a fastener 47. Heat dissipation fins 51 are provided on the outer surface of the heat dissipation section 45. The heat dissipation section 45 is made of a bimetallic material. That is, the heat dissipation section 45 is made of a bimetallic material having a first layer 45A on the side of the heat conduction section 23 and a second layer 45B on the opposite side of the heat conduction section 23, with the first layer 45A in between.

[0031] In the heat dissipation section 45, the coefficient of linear expansion of the material constituting the first layer 45A is configured to be greater than the coefficient of linear expansion of the material constituting the second layer 45B. Therefore, when the temperature of the heat dissipation section 45 rises, the heat dissipation section 45 deforms into a shape that increases the pressing force against the heat conduction section 23, and when the temperature of the heat dissipation section 45 falls, the heat dissipation section 45 deforms into a shape that decreases the pressing force against the heat conduction section 23.

[0032] By providing the heat dissipation section 45 configured in this way, the heat dissipation section 45 deforms according to the temperature. Therefore, when the electronic control unit 1 is operating, the thermal conductivity from the chip 17 to the heat dissipation section 45 can be improved, and when the electronic control unit 1 is stopped, the load on the solder ball 33 can be reduced.

[0033] Furthermore, in this embodiment, since the heat dissipation section 45 described above is adopted, the backplate section 25 adopted in the first embodiment can be omitted. Therefore, the structure near the substrate 13 can be simplified by eliminating the need for the backplate section 25, which can lead to a smaller overall device or to securing space for other components.

[0034] The heat dissipation section 45 described above may be mounted on the outside of the housing 11 as shown in Figure 10, or it may be mounted on the inside of the housing 11 as shown in Figure 11. (5) Other embodiments Although the electronic control device 1 has been described above with reference to exemplary embodiments, the above-described embodiments are merely illustrative examples of one aspect of the present disclosure. In other words, the present disclosure is not limited to the above-described exemplary embodiments and can be implemented in various forms without departing from the technical idea of ​​the present disclosure.

[0035] For example, in the above embodiment, a semiconductor module composed of an interposer 15 and a chip 17 was given as an example of an electronic component as referred to in this disclosure, but the specific form of the electronic component is not particularly limited.

[0036] Furthermore, although the above embodiment illustrates an air-cooled heat dissipation unit 21 equipped with heat dissipation fins 21A, the specific structure of the heat dissipation unit 21 is not particularly limited, and a heat dissipation unit 21 other than an air-cooled type may be used. For example, a water-cooled structure may be used instead of heat dissipation fins 21A to constitute a water-cooled heat dissipation unit.

[0037] Furthermore, multiple functions realized by one component as exemplified in the above embodiment may be realized by multiple components. One function realized by one component as exemplified in the above embodiment may be realized by multiple components. Multiple functions realized by multiple components as exemplified in the above embodiment may be realized by one component. One function realized by multiple components as exemplified in the above embodiment may be realized by one component. Some of the configurations exemplified in the above embodiment may be omitted. At least a part of the configuration exemplified in one of the above embodiments may be added to or replaced with the configuration exemplified in the other embodiments.

[0038] (6) The technical concept disclosed herein [Item 1] A substrate (13) having a first surface (13A) and a second surface (13B), The electronic components (15, 17) mounted on the first side, A heat dissipation section (21) is positioned opposite the first surface, A heat conduction section (23) is made of a thermal interface material and is positioned to be interposed between the electronic component and the heat dissipation section, A backplate portion (25) is constructed by laminating materials with different coefficients of linear expansion so as to be deformable according to temperature, and is positioned in a location that can contact the second surface, and deforms to a shape that increases the pressing force against the second surface when the temperature rises, and deforms to a shape that decreases the pressing force against the second surface when the temperature falls, An electronic control device (1) equipped with the following:

[0039] [Item 2] The electronic control device described in item 1, The backplate portion has a first layer (25A) on the substrate side and a second layer (25B) on the opposite side of the substrate, with the first layer in between, and is configured such that the coefficient of thermal expansion of the material constituting the first layer is greater than the coefficient of thermal expansion of the material constituting the second layer. Electronic control unit.

[0040] [Item 3] An electronic control device as described in item 1 or item 2, The aforementioned thermal interface material is a soft material, The heat conduction portion is configured to deform in accordance with the deformation of the electronic component when the electronic component is displaced due to the deformation of the back plate portion. Electronic control unit.

[0041] [Item 4] An electronic control device described in any one of items 1 to 3, The backplate portion is attached to the intermediate member (41) which is positioned between the backplate portion and the substrate, When the backplate portion deforms, the intermediate member is configured to transmit a pressing force from the backplate portion to the second surface, and in this case, the intermediate member is configured to transmit the pressing force to the second surface at multiple points. Electronic control unit.

[0042] [Item 5] An electronic control device described in any one of items 1 to 4, The backplate portion is attached to the soft member (43) and is positioned between the backplate portion and the substrate, When the backplate portion deforms, the pressing force is transmitted from the backplate portion to the second surface via the soft member, and the soft member is configured to transmit the pressing force over the entire area between both ends of the soft member. Electronic control unit.

[0043] [Item 6] An electronic control device described in any one of items 1 to 5, A part of the housing is positioned on the opposite side of the circuit board from the backplate portion, The backplate portion is attached to a part of the housing. Electronic control unit.

[0044] [Item 7] An electronic control device described in any one of items 1 through 6, The backplate portion is formed in a frame shape. Electronic control unit.

[0045] [Item 8] A substrate (13) having a first surface (13A) and a second surface (13B), The electronic components (15, 17) mounted on the first side, A heat dissipation section (45) is positioned opposite the first surface, A heat conduction section (23) is made of a thermal interface material and is positioned to be interposed between the electronic component and the heat dissipation section, Equipped with, The heat dissipation section is constructed by laminating materials with different coefficients of linear expansion, allowing it to deform according to the temperature. It is configured to deform to increase the pressure on the heat conduction section when the temperature rises, and to decrease the pressure on the heat conduction section when the temperature falls. Electronic control unit.

[0046] [Item 9] The electronic control device described in item 8, The heat dissipation section is configured to be in contact with the heat conduction section on one side, and a heat dissipation fin (51) is provided on the other side opposite to the one side. Electronic control unit. [Explanation of Symbols]

[0047] 1...Electronic control unit, 11...Housing, 11A...Upper housing, 11B...Lower housing, 11C, 31, 47...Fixing device, 13...Circuit board, 13A...First surface, 13B...Second surface, 15...Interposer, 17...Chip, 21, 45...Heat dissipation section, 21A, 51...Heat dissipation fins, 23...Heat conduction section, 25...Backplate section, 25A, 45A...First layer, 25B, 45B...Second layer, 33...Solder ball, 35...Mounting hole, 37...Shaft section, 39...Retaining member, 41...Intermediate member, 43...Soft member.

Claims

1. A substrate (13) having a first surface (13A) and a second surface (13B), The electronic components (15, 17) mounted on the first surface, A heat dissipation section (21) is positioned opposite the first surface, A heat conduction section (23) is made of a thermal interface material and is positioned to be interposed between the electronic component and the heat dissipation section, A backplate portion (25) is constructed by laminating materials with different coefficients of linear expansion so as to be deformable according to temperature, and is positioned in a location that can contact the second surface, and deforms to a shape that increases the pressing force against the second surface when the temperature rises, and deforms to a shape that decreases the pressing force against the second surface when the temperature falls, An electronic control device (1) equipped with the following:

2. The electronic control device according to claim 1, The backplate portion has a first layer (25A) on the substrate side and a second layer (25B) on the opposite side of the substrate, with the first layer in between, and is configured such that the coefficient of thermal expansion of the material constituting the first layer is greater than the coefficient of thermal expansion of the material constituting the second layer. Electronic control unit.

3. An electronic control device according to claim 1 or claim 2, The aforementioned thermal interface material is a soft material, The heat conduction portion is configured to deform in accordance with the deformation of the electronic component when the electronic component is displaced due to the deformation of the back plate portion. Electronic control unit.

4. An electronic control device according to claim 1 or claim 2, The backplate portion is attached to the intermediate member (41) which is positioned between the backplate portion and the substrate, When the backplate portion deforms, the intermediate member is configured to transmit a pressing force from the backplate portion to the second surface, and in this case, the intermediate member is configured to transmit the pressing force to the second surface at multiple points. Electronic control unit.

5. An electronic control device according to claim 1 or claim 2, The backplate portion is attached to the soft member (43) and is positioned between the backplate portion and the substrate, When the backplate portion deforms, the pressing force is transmitted from the backplate portion to the second surface via the soft member, and the soft member is configured to transmit the pressing force over the entire area between both ends of the soft member. Electronic control unit.

6. An electronic control device according to claim 1 or claim 2, A part of the housing is positioned on the opposite side of the circuit board from the backplate portion, The backplate portion is attached to a part of the housing. Electronic control unit.

7. An electronic control device according to claim 1 or claim 2, The backplate portion is formed in a frame shape. Electronic control unit.

8. A substrate (13) having a first surface (13A) and a second surface (13B), The electronic components (15, 17) mounted on the first surface, A heat dissipation section (45) is positioned opposite the first surface, A heat conduction section (23) is made of a thermal interface material and is positioned to be interposed between the electronic component and the heat dissipation section, Equipped with, The heat dissipation section is constructed by laminating materials with different coefficients of linear expansion, allowing it to deform according to the temperature. It is configured to deform to increase the pressure on the heat conduction section when the temperature rises, and to decrease the pressure on the heat conduction section when the temperature falls. Electronic control unit.

9. The electronic control device according to claim 8, The heat dissipation section is configured to be in contact with the heat conduction section on one side, and a heat dissipation fin (51) is provided on the other side opposite to the one side. Electronic control unit.

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