Electronic device

Abstract

This electronic device is provided with: a substrate (3) that has an upper surface (3a) and a lower surface (3b) that are in a front-and-back relationship, and that has a through-hole (31) that connects the upper surface and the lower surface, and a conductive film (32) that covers the wall surface of the through-hole; a terminal (4) that is inserted into the through-hole from the upper surface side; heat-generating members (5, 9, 10, 11, 12, 41) that are mounted on the lower surface; and a heat-dissipating member (8) that is disposed facing the lower surface, has higher thermal conductivity than the substrate, and is thermally connected to the heat-generating members.

Description

electronic equipment CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Patent Application No. 2024-52023, filed on March 27, 2024, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to an electronic device having terminals connected to a substrate on which a heat-generating component is mounted.

[0003] Conventional electronic devices of this type include, for example, the one described in Patent Document 1. The electronic device described in Patent Document 1 has a structure in which a plurality of heat-generating components, such as CPUs and integrated circuit elements, are mounted on a circuit board, and press-fit terminals are inserted into through holes provided in the circuit board and held in place by pressure. CPU is an abbreviation for Central Processing Unit. In this electronic device, a heat dissipation member, such as a heat pipe, is connected to the press-fit terminals, enabling heat dissipation through the press-fit terminals.

[0004] Japanese Patent Application Laid-Open No. 2008-283154

[0005] This type of electronic device may be configured, for example, such that a circuit board on which a heat-generating component is mounted is placed on a heat-dissipating component such as a housing, and heat from the heat-generating component is dissipated to the housing via the circuit board while preventing direct contact between the terminals, such as press-fit terminals, and the housing. The heat dissipation properties of an electronic device configured in this way can be further improved by, for example, placing a heat-dissipating gel between the circuit board and the heat-dissipating component.

[0006] However, in an electronic device with the above structure, it is necessary to form a recess such as a recess or a step in the heat dissipation member in the area directly below the terminal so that the portion of the terminal that protrudes from the through hole in the circuit board does not come into contact with the heat dissipation member. Furthermore, if a recess is formed in the heat dissipation member, the heat dissipation gel placed between the circuit board and the heat dissipation member may sink into the recess, reducing the heat dissipation performance of the terminal.

[0007] The present disclosure relates to an electronic device in which the heat dissipation performance of a heat-generating member is improved while preventing contact between a terminal and the heat dissipation member without processing the heat dissipation member.

[0008] According to one aspect of the present disclosure, an electronic device comprises: a substrate having upper and lower surfaces that are opposite sides of each other, a through hole connecting the upper and lower surfaces, and a conductive film covering the wall surface of the through hole; a terminal inserted into the through hole from the upper surface side; a heat-generating member mounted on the lower surface; and a heat-dissipating member arranged opposite the lower surface, having higher thermal conductivity than the substrate, and thermally connected to the heat-generating member.

[0009] This electronic device has a structure in which terminals are inserted from the top side into through holes in a substrate having an upper surface and a lower surface, and a heat-generating component is mounted on the lower surface, thermally connected to a heat dissipation component facing the lower surface. Therefore, compared to conventional structures in which a heat-generating component is mounted on the top surface, this electronic device has a shorter distance between the heat-generating component and the heat dissipation component, improving heat dissipation. Furthermore, by mounting the heat-generating component on the lower surface of this electronic device, a gap at least equal to the height of the heat-generating component is secured between the lower surface and the heat dissipation component, preventing the portions of the terminals that protrude from the through holes to the lower surface from contacting the heat dissipation component. Therefore, this electronic device does not require a recess in the heat dissipation component to prevent contact with the terminals.

[0010] FIG. 1 is an exploded perspective view showing an outline of an electronic device of a first embodiment; FIG. 2 is a cross-sectional view showing a portion of the electronic device of the first embodiment where terminals are inserted and the vicinity thereof; FIG. 3 is a diagram showing thermal analysis results of electronic devices of comparative examples and examples; FIG. 4 is a cross-sectional view corresponding to FIG. 2 and showing a modified example of the electronic device of the first embodiment; FIG. 5 is a cross-sectional view corresponding to FIG. 2 and showing an electronic device of a second embodiment; FIG. 6 is a cross-sectional view corresponding to FIG. 2 and showing an electronic device of a third embodiment; FIG. 7 is a front view showing an example of a shape of a terminal cover as seen from the underside of the board; FIG. 8 is a front view showing another example of a shape of the terminal cover as seen from the underside of the board; FIG. 9 is a cross-sectional view corresponding to FIG. 2 and showing an electronic device of a fourth embodiment; FIG. 10 is a cross-sectional view showing a first modified example of a conductive tube in the electronic device of the fourth embodiment; FIG. 11 is a cross-sectional view showing a second modified example of a conductive tube in the electronic device of the fourth embodiment; FIG. 12 is a cross-sectional view showing a third modified example of a conductive tube in the electronic device of the fourth embodiment; Fig. 1 is a cross-sectional view showing the vicinity of a filling member in an electronic device according to a fifth embodiment; Fig. 2 is a front view showing an example of the shape of a filling member as viewed from the underside of a substrate; Fig. 3 is a cross-sectional view showing an electronic device according to a sixth embodiment, corresponding to Fig. 2; Fig. 4 is a cross-sectional view showing a first modified example of the electronic device according to the sixth embodiment, corresponding to Fig. 2; Fig. 5 is a cross-sectional view showing a second modified example of the electronic device according to the sixth embodiment, corresponding to Fig. 2;

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. In the following embodiments, identical or equivalent parts will be denoted by the same reference numerals.

[0012] First Embodiment An electronic device 1 according to a first embodiment will be described below. In Fig. 1, the outline of a heat generating member 5 mounted on a lower surface 3b of a substrate 3 (to be described later) is indicated by a broken line.

[0013] [Basic Configuration] As shown in FIG. 1 , the electronic device 1 of this embodiment includes an upper housing 2, a substrate 3, terminals 4, a heat-generating member 5, electronic components 6, a heat dissipation material 7, and a lower housing 8. As shown in FIG. 2 , the electronic device 1 includes a substrate 3 housed in an internal space defined by the upper housing 2 and the lower housing 8, and the terminals 4 are inserted through a connector 21 of the upper housing 2. The heat-generating member 5 is mounted on the surface of the substrate 3 facing the lower housing 8, and the heat-generating member 5 and the lower housing 8 are thermally connected through the heat dissipation material 7. The electronic device 1 is suitable for use in control devices for electrical components that generate a large current when driven, such as various ECUs for automotive applications, but can also be used for other purposes. ECU stands for Electronic Control Unit.

[0014] The upper housing 2 is made of, for example, any resin material, and is a member that covers the substrate 3 and the heat-generating member 5 and electronic components 6 mounted thereon. The upper housing 2 is formed with, for example, a plurality of connecting portions 21 each having an opening 211 into which a terminal 4 to be connected to the substrate 3 can be inserted, and is configured to cover the top surface 3a side of the substrate 3 while allowing other members to be connected to the substrate 3. The upper housing 2 has, for example, a fastening portion such as a mating claw (not shown), and is configured to be attachable to the lower housing 8.

[0015] The substrate 3 is a plate-like member having an upper surface 3a and a lower surface 3b, which are opposite surfaces, and is also referred to as a printed circuit board or a circuit board. The substrate 3 has a base made of an insulating material, such as glass epoxy resin, and has a plurality of through holes 31 connecting the upper surface 3a and the lower surface 3b. As shown in FIG. 2 , the substrate 3 has a conductive film 32 covering the inner wall surfaces of the through holes 31 and wiring 33. The conductive film 32 is made of an electrically conductive material, such as copper, and covers the inner wall surfaces of the through holes 31 as well as the areas of the upper surface 3a and the lower surface 3b near the through holes 31, and is connected to the wiring 33. The wiring 33 includes, for example, an upper surface wiring 331 formed on the upper surface 3a, an internal wiring 332 formed inside the substrate 3, and a lower surface wiring 333 formed on the lower surface 3b. The wiring 33 is formed using an electrically conductive material by a known wiring formation technique and has an arbitrary pattern shape. The substrate 3 has, for example, terminals 4 inserted into through holes 31, a plurality of electronic components 6 mounted on the upper surface 3a, and a heat-generating member 5 mounted on the lower surface 3b. The substrate 3 has, for example, screw holes (not shown) provided near the four corners, and is attached to the lower housing 8 with screws (not shown), while the areas of the lower surface 3b other than those near the screw holes do not come into contact with the lower housing 8.

[0016] The terminals 4 are well-known terminals, such as press-fit terminals, and are inserted from the top surface 3 a side through the openings 211 in the upper housing 2 into the through-holes 31 in the substrate 3. For example, a plurality of terminals 4 are inserted into the substrate 3 and electrically connected to the heat-generating member 5 and the electronic components 6 via the conductive film 32 and the top surface wiring 331 or the bottom surface wiring 333. For example, the tip portions of the terminals 4 protrude from the through-holes 31 toward the bottom surface 3 b and are thermally connected to the lower housing 8 via the heat dissipation material 7. The terminals 4 do not contact the lower housing 8 and are electrically insulated from the lower housing 8. The portions of the terminals 4 protruding from the bottom surface 3 b of the substrate 3 are called protruding portions 41, and the protruding portions 41 have a height, for example, at least less than the height of the heat-generating member 5 so as not to come into direct contact with the lower housing 8.

[0017] The heat-generating member 5 is a power semiconductor module including semiconductor components, such as MOSFETs and IGBTs, that generate a large current when driven. MOSFETs and IGBTs are abbreviations for Metal Oxide Semiconductor Field Effect Transistor and Insulated Gate Bipolar Transistor, respectively. The heat-generating member 5 is mounted on the lower surface 3b of the substrate 3, connected to the lower surface wiring 333 via a bonding material 55 made of a conductive bonding material such as solder, and electrically connected to the terminals 4. The heat-generating member 5 is disposed, for example, separated from the lower housing 8 by a gap and thermally connected to the lower housing 8 via a heat dissipation material 7. This allows heat generated by the heat-generating member 5 during driving to be efficiently conducted to the lower housing 8 via the heat dissipation material 7, thereby suppressing temperature rise.

[0018] As shown in FIG. 2 , the heat-generating member 5 includes, for example, a lead frame 51, a semiconductor element 52, a conductive clip 53, and a sealing resin 54. The heat-generating member 5 includes, for example, a lead frame 51 on which the semiconductor element 52 is mounted, and a plate-shaped conductive clip 53 is connected to the surface of the semiconductor element 52 opposite the lead frame 51. The heat-generating member 5 has, for example, a structure in which the surface of the lead frame 51 opposite the semiconductor element 52 is exposed from the sealing resin 54, and the semiconductor element 52 and the conductive clip 53 are covered by the sealing resin 54. However, the heat-generating member 5 may have a structure in which only a portion of the conductive clip 53 is exposed from the sealing resin 54. The heat-generating member 5 has, for example, an nin-in-one structure in which n semiconductor elements 52 are enclosed within the sealing resin 54, where n is the number of semiconductor elements 52 (n: an integer greater than or equal to 1). The lead frame 51 is made of any conductive material, such as copper, and has a predetermined pattern shape. The semiconductor element 52 is, for example, a power semiconductor element manufactured by a known semiconductor manufacturing process, such as a power MOSFET, and at least one is mounted on the lead frame 51. The conductive clip 53 is made of any conductive material, such as copper, and is a bridging member that bridges and electrically connects the semiconductor element 52 to a portion of the lead frame 51, and may also be called a metal clip. The sealing resin 54 is made of any insulating resin material, such as epoxy resin, and is a member that covers the semiconductor element 52 and the like.

[0019] For example, a plurality of electronic components 6 are mounted on the upper surface 3a of the substrate 3 and are electrically connected to the upper surface wiring 331 via bonding materials 61 made of a conductive bonding material such as solder. The electronic components 6 are various elements that can be used in electronic circuits, such as power relays, coils, electrolytic capacitors, motor relays, microcomputers, control ICs, resistors, bus bars, etc. IC is an abbreviation for Integrated Circuit.

[0020] The heat dissipation material 7 is a material that, for example, fills a portion of the gap between the underside 3b of the substrate 3 and the lower housing 8, thereby thermally connecting at least a portion of the substrate 3 and the heat-generating component 5 to the lower housing 8 and dissipating heat from the substrate 3 and the heat-generating component 5 to the lower housing 8. The heat dissipation material 7 is electrically insulating and has a thermal conductivity higher than that of air, and is made of, for example, a known heat dissipation gel, heat dissipation sheet, or heat dissipation adhesive. The heat dissipation material 7 is arranged, for example, to fill the gap between the lower housing 8 and the region of the substrate 3 that generates a large amount of heat during operation and the heat-generating component 5. The heat dissipation material 7 is also arranged, for example, to fill the gap between the terminal 4 and the lower housing 8, providing a heat conduction path that dissipates heat from the terminal 4 to the lower housing 8.

[0021] The lower housing 8 is a member that forms a pair with the upper housing 2 and covers the lower surface 3b side of the substrate 3. The lower housing 8 is made of, for example, a metal material such as aluminum or an alloy thereof, or a metal-resin composite material such as a highly heat-dissipating resin material containing a heat-dissipating filler, and is a heat-dissipating member that plays a role in dissipating heat from the substrate 3 and the heat-generating member 5 to the outside. The lower housing 8 may have any heat-dissipating structure, such as a heat-dissipating fin (not shown), for improving heat dissipation.

[0022] The above is the basic configuration of the electronic device 1 of this embodiment.

[0023] [Heat Dissipation] Next, the effect of improving heat dissipation by the structural model of the electronic device 1 (hereinafter referred to as the "Example") will be explained based on the results of thermal analysis comparing it with the structural model of the electronic device 100 (hereinafter referred to as the "Comparative Example") shown in Figure 3 as a comparative example.

[0024] Although FIG. 3 does not show a cross section, hatching is used to make it easier to understand the temperature distribution as a result of the thermal analysis, and areas with a greater temperature rise as a result of the thermal analysis are shown with hatching that is closer to black.

[0025] 3 , the comparative example differs from the example in that a heat-generating member 5 is mounted on the upper surface 3a of the substrate 3, and a recessed portion 111 is formed in a region of the lower housing 110 located directly below the terminal 4. In the comparative example, a heat dissipation material 7 is disposed in a region of the lower surface 3b of the substrate 3 located directly below the region where the heat-generating member 5 is mounted, and the gap between this region and the lower housing 110 is filled with the heat dissipation material 7. In the comparative example, the gap between the lower surface 3b of the substrate 3 and a protrusion 112 of the lower housing 110 adjacent to the recessed portion 111, i.e., the thickness of the heat dissipation material 7, is 1 mm. In the comparative example, a current path is formed on the upper surface 3a of the substrate 3 through the terminal 4, the upper surface wiring 331, and the heat-generating member 5, and heat generated in this current path is transferred to the lower housing 8 via the substrate 3 and the heat dissipation material 7.

[0026] In the comparative example and the example, through holes 31 and conductive films 32 are formed on both sides of the heat-generating member 5 in the substrate 3, and press-fit connectors are inserted into these as terminals 4. In the comparative example and the example, the thickness of the substrate 3 is the same, 1.6 mm or more. In the comparative example and the example, a plurality of through electrodes 34 connecting the wiring 331 to 333 are formed on the substrate 3. In the comparative example and the example, the lower housings 8 and 110 are made of aluminum, the heat dissipation material 7 is a heat dissipation gel, and the heat-generating member 5 is a power MOSFET.

[0027] In the embodiment, for example, the gap between the region of the underside 3b where the heat-generating member 5 is mounted and the lower housing 8 is 1.4 mm, and the gap between the heat-generating member 5 and the lower housing 8 is 0.5 mm. In the embodiment, a current path is provided on the underside 3b of the substrate 3 through the terminals 4, the underside wiring 333, and the heat-generating member 5, and heat generated in the current path is transferred to the lower housing 8 via the heat dissipation material 7. Note that the above embodiment is an example of a sealing structure in which the surface of the heat-generating member 5 opposite the substrate 3 is completely covered with the sealing resin 54, ensuring insulation. For example, in a sealing structure in which a portion of the surface of the heat-generating member 5 opposite the substrate 3 is exposed from the sealing resin 54, the gap between the heat-generating member 5 and the lower housing 8 is 1 mm in the embodiment.

[0028] For the comparative example and the example, the temperature distribution was analyzed when the heat-generating member 5 was driven under the same conditions using known thermal analysis simulation software. The conditions for the thermal analysis were as follows:

[0029] <Conditions for thermal analysis> Wiring: Length L from terminal 4 to heat-generating member 5 was 20 mm, width W was 5 mm Current value: drive current for heat-generating member 5 was 1 A As a result of the thermal analysis, in the comparative example, the temperature of the upper surface wiring 331 near terminal 4 rose by 8.6°C and the temperature of the heat-generating member 5 rose by 3.1°C due to the application of current. On the other hand, in the example, the temperature of the lower surface wiring 333 near terminal 4 rose by 6.7°C and the temperature of the heat-generating member 5 rose by 1.4°C due to the application of current, and the temperature rise of the wiring and heat-generating member 5 was suppressed more than in the comparative example. This is thought to be due to the fact that in the example, heat-generating member 5 was disposed on the lower surface 3b and the distance between the heat-generating member 5 and the lower housing 8, which is a heat dissipation member, was shorter than in the comparative example, making it easier for heat from the heat-generating member 5 to dissipate to the lower housing 8 without passing through the board 3.

[0030] According to this embodiment, terminals are inserted into the through holes 31 of the substrate 3 from the top surface 3a, a heat-generating member 5 is mounted on the bottom surface 3b, and the heat-generating member 5 is thermally connected to the lower housing 8 facing the bottom surface 3b via the heat dissipation material 7. Therefore, in the electronic device 1, the distance between the heat-generating member 5 and the heat dissipation member is shorter than in the comparative example in which the heat-generating member 5 is mounted on the top surface 3a, thereby improving heat dissipation. Furthermore, in this electronic device 1, by mounting the heat-generating member 5 on the bottom surface 3b, a gap at least equal to the height of the heat-generating member 5 is secured between the bottom surface 3b and the lower housing 8. Therefore, in the electronic device 1, contact between the protruding portions 41 of the terminals 4 protruding from the bottom surface 3b and the lower housing 8 is suppressed without requiring a recess in the lower housing 8 to prevent contact with the terminals 4.

[0031] 4, the electronic device 1 may have a sealing structure in which the surface of the heat-generating member 5 opposite the substrate 3 is completely covered with sealing resin 54 to ensure insulation, and the heat-generating member 5 may be in contact with the lower housing 8. In this case, the electronic device 1 may not have a heat dissipation material 7, or the heat dissipation material 7 may be disposed in an area of ​​the lower surface 3b of the substrate 3 that is different from the area where the heat-generating member 5 is mounted.

[0032] This modification also provides the electronic device 1 with the same effects as those of the first embodiment.

[0033] Second Embodiment An electronic device 1 according to a second embodiment will be described.

[0034] 5, the electronic device 1 of this embodiment differs from the first embodiment in that, in addition to the heat-generating member 5, a bus bar 9 is mounted on the lower surface 3b of the substrate 3. This difference will be mainly described in this embodiment.

[0035] The bus bar 9 is made of a conductive material such as metal and is a generally plate-shaped member that reduces the wiring resistance of the underside wiring 333. The bus bar 9 is connected to the underside wiring 333 via a bonding material 91 made of a conductive bonding material such as solder, and serves as a current path on the underside 3b. The bus bar 9 is covered with a heat dissipation material 7, for example, and is thermally connected to the lower housing 8 via the heat dissipation material 7 while being electrically insulated from the lower housing 8. As a result, the electronic device 1 of this embodiment is configured such that the amount of heat generated on the underside 3b is suppressed by the reduction in wiring resistance due to the bus bar 9, and a heat dissipation path is provided in which heat on the underside 3b side is transferred to the lower housing 8 via the bus bar 9 and the heat dissipation material 7.

[0036] According to this embodiment, in addition to the same effects as the first embodiment, the electronic device 1 has the effect of increasing the number of heat dissipation paths to the lower housing 8 by having the bus bar 9, thereby further improving heat dissipation.

[0037] Third Embodiment An electronic device 1 according to a third embodiment will be described. In Figures 7 and 9, the outline of the protruding portion 41 of the terminal 4, which is covered by the terminal cover 10 described later, is indicated by a broken line when viewed from the underside 3b.

[0038] 6, the electronic device 1 of this embodiment differs from the first embodiment in that it further includes a terminal cover 10 that covers the periphery of the portion of the terminal 4 that protrudes from the lower surface 3b. In this embodiment, this difference will be mainly described.

[0039] As shown in FIGS. 6 and 7 , the terminal cover 10 is a member that surrounds the through-holes 31 and the protruding portions 41 of the terminals 4 inserted therein. Hereinafter, for ease of explanation, the through-holes 31 into which the terminals 4 are inserted may be referred to as "terminal through-holes." When viewed from a direction normal to the bottom surface 3b, the terminal cover 10 has a bottomed, cylindrical shape including a base 10a that surrounds one or more terminal through-holes across a gap and a lid 10b that closes the end of the base 10a opposite the board 3. The terminal cover 10 is made of, for example, a conductive metal material or its alloy material with high thermal conductivity and is thermally connected to the lower housing 8 by a heat sink 7. This allows the terminal cover 10 to more easily transfer heat near the terminals 4 to the lower housing 8 and prevents electromagnetic noise from other locations from entering the terminals 4. Furthermore, the terminal cover 10 prevents the heat dissipation material 7 from entering the terminal through-holes, and thus prevents poor contact between the terminals 4 and the conductive film 32 caused by the heat dissipation material 7 .

[0040] The terminal cover 10 may be a bottomless cylindrical shape having only a base 10a, as shown in Fig. 8. Alternatively, the terminal covers 10 may be attached to the terminal through-holes one by one, covering the terminal through-holes individually, as shown in Fig. 9. In this case, the terminal covers 10 have, for example, wall portions 10c arranged on both sides of the terminal through-holes and the protruding portions 41 of the terminals 4, and lid portions 10b connecting the tips of the wall portions 10c and covering the protruding portions 41, and are attached side by side with their orientations aligned.

[0041] According to this embodiment, in addition to the same effects as those of the first embodiment, the electronic device 1 has the effect of further improving heat dissipation by increasing the number of heat dissipation paths to the lower housing 8 due to the inclusion of the terminal cover 10. Furthermore, if the terminal cover 10 of this electronic device 1 is made of a conductive material, the inflow of electromagnetic noise from other parts to the terminals 4 is suppressed, thereby improving reliability.

[0042] Fourth Embodiment An electronic device 1 according to a fourth embodiment will be described.

[0043] 10, the electronic device 1 of this embodiment differs from the first embodiment in that it further includes a conductive tube 11 that is inserted into a through hole 31. This difference will be mainly described in this embodiment.

[0044] The conductive tube 11 has, for example, a bottomless cylindrical tube portion 11a and an annular flange 11b at one end of the tube portion 11a, with the extension direction being along the axis of the tube portion 11a. The conductive tube 11 is made of any conductive material, for example, copper, and is press-fitted into the through-hole 31 to electrically connect to the conductive film 32. For example, the inner diameter of the tube portion 11a is equal to or smaller than the outer diameter of the terminal 4, and the conductive tube 11 serves to hold the inserted terminal 4 and improve the connection strength with the terminal 4. For example, the tube portion 11a of the conductive tube 11 is inserted from the bottom surface 3b, and the flange 11b connects to the bottom surface wiring 333 on the bottom surface 3b, thereby reducing the electrical resistance and thermal resistance of the bottom surface wiring 333. The conductive tube 11 also serves to reduce the electrical resistance and thermal resistance in the thickness direction of the substrate 3 through the tube portion 11a, and may also be referred to as a busbar collar. When the conductive cylinder 11 is a cylindrical body without a bottom, the heat dissipation material 7 is arranged so as not to enter the conductive cylinder 11 and not to come into contact with the conductive cylinder 11, for example.

[0045] According to this embodiment, in addition to the same effects as those of the first embodiment, the electronic device 1 has the conductive tube 11, which reduces the electrical resistance and thermal resistance in the thickness direction of the substrate 3 and also improves the connection strength with the terminals 4. Furthermore, when the conductive tube 11 has the flange 11b, the electronic device 1 is electrically connected to the upper surface wiring 331 or the lower surface wiring 333, thereby achieving the effect of reducing wiring resistance.

[0046] 11 , the conductive tube 11 may have a flange 11b formed at a position away from the end of the tube portion 11a in the extension direction, and a lid portion 11c that closes the end. When the lid portion 11c is provided, the heat dissipation material 7 is disposed to cover the lid portion 11c of the conductive tube 11, thermally connecting the conductive tube 11 and the lower housing 8. This provides the electronic device 1 with a heat dissipation path to the lower housing 8 via the conductive tube 11 and the heat dissipation material 7, further improving heat dissipation.

[0047] According to this modified example, in addition to the same effects as those of the above-mentioned fourth embodiment, the conductive tube 11 is thermally connected to the lower housing 8 via the heat dissipation material 7, resulting in an electronic device 1 which also has the effect of further improving the heat dissipation properties of the terminals 4.

[0048] (Second Modification of Fourth Embodiment) The conductive cylinder 11 may have a configuration in which the cylinder portion 11a is a bottomed cylinder having a lid portion 11c, and does not have a flange 11b, as shown in FIG. 12, for example.

[0049] This modification also provides the electronic device 1 with the same effects as the first modification.

[0050] 13, the conductive tube 11 may have a cylindrical shape with a bottom, a tubular portion 11a having a lid portion 11c, and a flange 11b formed on the opening side of the tubular portion 11a opposite to the lid portion 11c. In this case, the conductive tube 11 is inserted into the through hole 31 from the top surface 3a side, and the flange 11b is electrically connected to the top surface wiring 331.

[0051] This modification also provides the electronic device 1 with the same effects as the first modification.

[0052] 14 , the conductive tube 11 may have a cylindrical portion 11a that is elliptical when viewed from the extension direction, and may have a protrusion 11d that extends from a portion of the cylindrical portion 11a that has a smaller outer diameter. The protrusion 11d extends, for example, in a radial direction with the extension direction as its axis, and serves to press-fit and hold the conductive tube 11 when inserted into the through-hole 31. Because the cylindrical portion 11a of the conductive tube 11 is elliptical, when a press-fit terminal is used as the terminal 4, the terminal 4 is positioned in the direction of the cylindrical portion 11a that has a larger inner diameter, which suppresses rotation of the terminal 4 and prevents poor fitting with the terminal 4.

[0053] According to this modified example, in addition to the effects of the above-described fourth embodiment, the cylindrical portion 11a of the conductive tube 11 is elliptical cylindrical, so that the terminal 4 is positioned, and the electronic device 1 has the effect of suppressing rotation of the terminal 4 and the resulting poor contact.

[0054] 15, the conductive tube 11 may have a cylindrical portion 11a that is substantially circular when viewed from the extension direction, and may have a slit portion 11e on the inner wall surface that can fit with the terminal 4. Even in this case, when a press-fit terminal is used as the terminal 4, the conductive tube 11 positions the terminal 4 in the slit portion 11e, thereby suppressing rotation of the terminal 4 and preventing poor fitting.

[0055] This modification also provides the electronic device 1 with the same effects as the fourth modification.

[0056] (Sixth Modification of the Fourth Embodiment) Furthermore, as shown in FIG. 16 , the inner wall surface of the cylindrical portion 11a of the conductive tube 11 may be welded to the terminal 4. For example, with the terminal 4 inserted into the cylindrical portion 11a of the conductive tube 11, a pair of electrodes (not shown) may be connected to the terminal 4 and the conductive tube 11, respectively, and a current of a predetermined level or higher may be applied to weld the terminal 4 and the conductive tube 11. This improves the bonding strength between the terminal 4 and the conductive tube 11, reduces the contact resistance between the terminal 4 and the conductive tube 11, and ultimately reduces impedance, thereby improving the reliability of the electronic device 1. The terminal 4 may be welded to the conductive tube 11 before or after inserting the conductive tube 11 into the through-hole 31.

[0057] According to this modified example, in addition to the effects of the fourth embodiment, the electronic device 1 has the effect of reducing the contact resistance and impedance between the terminal 4 and the conductive tube 11 by welding them, thereby further improving reliability.

[0058] In addition, the electronic device 1 according to this embodiment and its modified examples may be freely combined or used in conjunction with the above-mentioned configuration of the conductive tube 11 and the fitting or welding with the terminal 4, except in cases where they are clearly incompatible.

[0059] Fifth Embodiment An electronic device 1 according to a fifth embodiment will be described.

[0060] 17, the electronic device 1 of this embodiment differs from the first embodiment in that it further includes filler members 12 attached to through holes 31 of the substrate 3 that do not have terminals 4 inserted therein. This difference will be mainly described in this embodiment.

[0061] The filler 12 is made of any conductive material, such as copper, and is attached to the through-holes 31 other than the terminal through-holes to fill the through-holes 31. As shown in FIGS. 17 and 18 , the filler 12 has a cylindrical base 12a and a ring-shaped flange 12b extending from the axial end of the base 12a. The filler 12 abuts and electrically connects to the conductive film 32, forming one of the current paths of the electronic device 1 and reducing the electrical resistance and thermal resistance in the thickness direction of the substrate 3. The filler 12 is inserted into the through-hole 31 from the bottom surface 3b, for example, and the flange 12b is connected to the bottom surface wiring 333. The filler 12 may also be referred to as a collar. The filler 12 is thermally connected to the lower housing 8, for example, via a heat dissipation material 7, forming one of the heat dissipation paths.

[0062] According to this embodiment, in addition to the same effects as those of the first embodiment, the electronic device 1 has the effect of reducing the electrical resistance and thermal resistance in the thickness direction of the substrate 3 by having the filler member 12. Furthermore, in the electronic device 1, the filler member 12 is thermally connected to the lower housing 8 via the heat dissipation material 7, so that the number of heat dissipation paths for the substrate 3 is increased, thereby improving heat dissipation.

[0063] Sixth Embodiment An electronic device 1 according to a sixth embodiment will be described.

[0064] 19, the electronic device 1 of this embodiment differs from the first embodiment in that it further includes an insulating spacer 13 that thermally connects a member, which is different from the heat-generating member 5 and is mounted on the lower surface 3b of the substrate 3, to the lower housing 8. This difference will be mainly described in this embodiment.

[0065] 19 , the electronic device 1 has a bus bar 9 attached to the lower surface 3b of the substrate 3, and an insulating spacer 13 disposed between the bus bar 9 and the lower housing 8. The insulating spacer 13 is made of any electrically insulating material and is a member that abuts against both the bus bar 9 and the lower housing 8 to thermally connect them and serve as a heat dissipation path. By appropriately adjusting the thickness of the insulating spacer 13, it is possible to prevent direct contact between the heat-generating component 5 and the lower housing 8 while ensuring that the gap between them is equal to or smaller than a predetermined value. In other words, the insulating spacer 13 itself constitutes a heat dissipation path and also serves to increase thermal conductivity between the heat-generating component 5 and the lower housing 8, thereby further improving heat dissipation.

[0066] According to this embodiment, in addition to the features of the second embodiment, the electronic device 1 has the insulating spacer 13, which allows heat from components other than the heat-generating component 5 mounted on the lower surface 3b to efficiently dissipate to the lower housing 8, thereby improving heat dissipation. Furthermore, the insulating spacer 13 in the electronic device 1 keeps the gap between the heat-generating component 5 and the lower housing 8 at a predetermined value or less, thereby increasing thermal conductivity while ensuring insulation between them, and thereby further improving the heat dissipation of the heat-generating component 5. Furthermore, the electronic device 1 has a structure in which the heat-generating component 5 and the lower housing 8 are reliably prevented from coming into contact with each other, which, in the case of an in-vehicle application, suppresses transmission of vehicle vibrations to the heat-generating component 5, thereby improving reliability by suppressing element damage caused by vibrations.

[0067] (First Modification of Sixth Embodiment) When the electronic device 1 has a terminal cover 10 instead of the bus bar 9, as shown in FIG. 20 for example, an insulating spacer 13 is disposed between the terminal cover 10 and the lower housing 8.

[0068] This modification also provides the electronic device 1 with the same effects as those of the sixth embodiment.

[0069] (Second Modification of Sixth Embodiment) The electronic device 1 may have a configuration including a conductive spacer 14 instead of the insulating spacer 13, as shown in FIG. 21 . In this case, the substrate 3 has, for example, a connection portion 35 on the lower surface 3 b, which is a conductive pattern electrically insulated from the lower surface wiring 333, and the conductive spacer 14 is connected to the connection portion 35. The conductive spacer 14 is made of any conductive material, such as copper, and thermally connects the connection portion 35 and the lower housing 8. By appropriately adjusting the thickness of the conductive spacer 14, similar to the insulating spacer 13, the conductive spacer 14 serves to prevent direct contact between the heat-generating member 5 and the lower housing 8 while keeping the gap therebetween at a predetermined value or less.

[0070] This modification also provides the electronic device 1 with the same effects as those of the sixth embodiment.

[0071] (Other Embodiments) While the present disclosure has been described with reference to examples, it is understood that the present disclosure is not limited to those examples or structures. The present disclosure also encompasses various modifications and modifications within the scope of equivalents. In addition, various combinations and forms, as well as other combinations and forms including only one element, more than one, or less than one, are also within the scope and spirit of the present disclosure.

[0072] In the above-described embodiments and their modified examples, a power semiconductor module is used as a representative example of the heat-generating member 5, but the present invention is not limited to this. For example, components that are mounted on or located on the lower surface 3b of the substrate 3 and that are electrically connected, such as the bus bar 9, the terminal cover 10, the conductive tube 11, the filling member 12, and the protruding portion 41 of the terminal 4, can also be considered heat-generating members. Therefore, unless clearly incompatible, heat-generating components other than the power semiconductor module, such as the bus bar 9, can be considered heat-generating members 5, and the structures of the above-described embodiments and their modified examples can be applied to the extent possible.

[0073] Furthermore, in each of the above embodiments, it goes without saying that the elements constituting the embodiments are not necessarily essential unless they are particularly explicitly stated as essential or are clearly considered essential in principle. Furthermore, in each of the above embodiments, when the numbers, values, amounts, ranges, etc. of the components of the embodiments are mentioned, they are not limited to the specific numbers unless they are particularly explicitly stated as essential or are clearly limited to a specific number in principle. Furthermore, in each of the above embodiments, when the shapes, positional relationships, etc. of the components are mentioned, they are not limited to the shapes, positional relationships, etc. unless they are particularly explicitly stated or are clearly limited to a specific shape, positional relationship, etc. in principle.

[0074] (Viewpoints of the Present Disclosure) The above-described present disclosure can be understood from the following viewpoints, for example.

[0075] [First Aspect] An electronic device comprising: a substrate (3) having an upper surface (3a) and a lower surface (3b) that are opposite surfaces, a through hole (31) connecting the upper surface and the lower surface, and a conductive film (32) covering the wall surface of the through hole; a terminal (4) inserted into the through hole from the upper surface side; a heat-generating member (5, 9, 10, 11, 12, 41) mounted on the lower surface; and a heat-dissipating member (8) arranged opposite the lower surface, having higher thermal conductivity than the substrate, and thermally connected to the heat-generating member. [Second Aspect] The electronic device according to the first aspect, further comprising an insulating heat-dissipating material (7) connecting the heat-generating member and the heat-dissipating member. [Third Aspect] The electronic device according to the first aspect, wherein the heat-generating member has a surface opposite to the substrate that is covered with insulating resin and is in contact with the heat-dissipating member. [Fourth Aspect] The electronic device according to the first or second aspect, wherein the heat-generating component is a semiconductor package having a power semiconductor element (52), a conductive clip (53) connected to the power semiconductor element, and an insulating sealing resin (54) covering the power semiconductor element, the side opposite to the substrate being completely covered with the sealing resin. [Fifth Aspect] The electronic device according to the second aspect, further including a plate-shaped bus bar (9) connected to the underside, the bus bar thermally connected to the heat dissipation component via the heat dissipation material. [Sixth Aspect] The electronic device according to the second aspect, further including a terminal cover (10) connected to the underside near the through hole, surrounding portions of the terminals protruding beyond the underside, and made of a material with higher thermal conductivity than the substrate, the terminal cover thermally connected to the heat dissipation component via the heat dissipation material. [Seventh Aspect] The electronic device according to any one of the first to sixth aspects, further comprising a cylindrical conductive tube (11) made of a conductive material, inserted into the through hole and in contact with the conductive film, wherein the terminals are press-fitted and held in the conductive tube. [Eighth Aspect] The electronic device according to the seventh aspect, further comprising a heat dissipation material (7) that connects the heat-generating component and the heat dissipation component, has higher thermal conductivity than the substrate, and is insulating, wherein the conductive tube has a closed end that protrudes from the lower surface, and is thermally connected to the heat dissipation component via the heat dissipation material.[Ninth Aspect] The electronic device according to the seventh or eighth aspect, wherein the conductive tube has an elliptical cylindrical portion at a portion where the terminal is inserted. [Tenth Aspect] The electronic device according to the seventh or eighth aspect, wherein the conductive tube has a slit portion (11e) on an inner wall surface where the terminal is inserted. [Eleventh Aspect] The electronic device according to any one of the seventh to tenth aspects, wherein the terminal is welded to the conductive tube. [Twelfth Aspect] The electronic device according to the second aspect, wherein the substrate has a plurality of the through holes and the conductive films, and further includes a filler member (12) made of a metal material inserted into any of the through holes other than the through hole into which the terminal is inserted, filling the other through holes, and the filler member is thermally connected to the heat dissipation member via the heat dissipation member. [Thirteenth Aspect] The electronic device according to any one of the first, second, fourth to twelfth aspects, wherein the substrate has a component (9, 10) different from the heat-generating component mounted on the underside thereof, and further comprises an insulating spacer (13) connecting the different component and the heat-dissipating component. [Fourteenth Aspect] The electronic device according to any one of the first, second, fourth to twelfth aspects, further comprises a conductive spacer (14) connecting the underside of the substrate and the heat-dissipating component, and wherein the conductive spacer is connected to a connection part (35) on the underside that is electrically insulated from at least a wiring connected to the heat-generating component.

Claims

1. An electronic device comprising: a substrate (3) having an upper surface (3a) and a lower surface (3b) that are opposite surfaces, a through hole (31) connecting the upper surface and the lower surface, and a conductive film (32) covering the wall surface of the through hole; a terminal (4) inserted into the through hole from the upper surface side; a heat-generating member (5, 9, 10, 11, 12, 41) mounted on the lower surface; and a heat-dissipating member (8) arranged opposite the lower surface, having a higher thermal conductivity than the substrate, and thermally connected to the heat-generating member.

2. The electronic device according to claim 1, further comprising an insulating heat dissipation material (7) connecting the heat generating member and the heat dissipation member.

3. The electronic device according to claim 1, wherein the heat generating member has a surface opposite to the substrate covered with insulating resin and in contact with the heat dissipating member.

4. The electronic device according to claim 1, wherein the heat-generating component is a semiconductor package having a power semiconductor element (52), a conductive clip (53) connected to the power semiconductor element, and an insulating sealing resin (54) covering the power semiconductor element, the side opposite to the substrate being completely covered with the sealing resin.

5. The electronic device according to claim 2, further comprising a plate-shaped bus bar (9) connected to the lower surface, the bus bar being thermally connected to the heat dissipation member via the heat dissipation material.

6. An electronic device as described in claim 2, further comprising a terminal cover (10) connected to the underside near the through hole, surrounding the portion of the terminal that protrudes beyond the underside, and made of a material with higher thermal conductivity than the substrate, wherein the terminal cover is thermally connected to the heat dissipation member via the heat dissipation material.

7. The electronic device according to claim 1, further comprising a cylindrical conductive tube (11) made of a conductive material, inserted into the through hole and in contact with the conductive film, and wherein the terminal is press-fitted and held in the conductive tube.

8. An electronic device as described in claim 7, further comprising a heat dissipation material (7) that connects the heat generating component and the heat dissipation component, has higher thermal conductivity than the substrate, and is insulating, and the conductive tube has a closed end that protrudes from the bottom surface and is thermally connected to the heat dissipation component via the heat dissipation material.

9. The electronic device according to claim 7, wherein the conductive tube has an elliptical cylindrical portion into which the terminal is inserted.

10. The electronic device according to claim 7, wherein the conductive tube has a slit portion (11e) on the inner wall surface into which the terminal is inserted.

11. The electronic device according to claim 7, wherein the terminal is welded to the conductive tube.

12. The electronic device of claim 2, wherein the substrate has a plurality of the through holes and the conductive films, and further has a filler member (12) made of a metal material that is inserted into any of the plurality of through holes other than the through hole into which the terminal is inserted and fills the other through holes, and the filler member is thermally connected to the heat dissipation member via the heat dissipation material.

13. An electronic device according to any one of claims 1, 2, 4 to 12, wherein the substrate has components (9, 10) different from the heat-generating component mounted on the underside thereof, and further has an insulating spacer (13) connecting the different components to the heat-dissipating component.

14. An electronic device according to any one of claims 1, 2, 4 to 12, further comprising a conductive spacer (14) connecting the underside of the substrate and the heat dissipation member, the conductive spacer being connected to a connection part (35) on the underside that is electrically insulated from at least the wiring connected to the heat-generating member.

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