Electronic component assembly, electronic component, and circuit board

Abstract

An electronic component assembly (1) comprises an electronic component (3), a heat dissipation member (29), and a leaf spring (31). A sealing body (17) in the electronic component (3) has a first main surface (17a) and a second main surface (17b) on opposite sides from each other. The first main surface (17a) is in contact with the heat dissipation member (29). A protrusion (19) is formed on the second main surface (17b). The second main surface (17b) includes the surface of the protrusion (19). The leaf spring (31) is fixed to the heat dissipation member (29) in a state in which the first main surface (17a) of the electronic component (3) is pressed against the heat dissipation member (29) by the elastic force generated by bending the leaf spring (31) contacting the protrusion (19).

Description

Electronic component assembly and electronic component, and circuit board

[0001] The present disclosure relates to electronic assemblies and components and circuit boards.

[0002] Electronic circuits use many electronic components that generate heat during operation. If the temperature of the electronic components exceeds a certain level, it can cause problems in the operation of the electronic circuit and may also shorten the lifespan of the electronic components.

[0003] To avoid such problems, some electronic components are combined with a heat dissipation member to prevent the temperature of the electronic component from rising above a certain temperature. Various methods have been devised to closely attach the electronic component to the heat dissipation member in order to efficiently dissipate the heat generated in the electronic component.

[0004] For example, Patent Document 1 proposes a power semiconductor device that uses a curved heat dissipation member, sandwiches a power semiconductor element between the curved heat dissipation member and a fixing member, and fixes it with bolts and nuts.

[0005] Japanese Patent Application Laid-Open No. 2021-72363

[0006] Electronic circuits are required to dissipate heat generated from electronic components more efficiently and easily.

[0007] The present disclosure has been made based on such developments, and one object of the present disclosure is to provide an electronic component assembly that can more efficiently and easily dissipate heat generated from electronic components, another object is to provide an electronic component that can be applied to such an electronic component assembly, and yet another object is to provide a circuit board in which such an electronic component assembly is mounted on a printed wiring board.

[0008] An electronic component assembly according to the present disclosure includes a heat dissipation member, an electronic component, and a plate-shaped elastic member. The electronic component includes a sealing body that seals an electronic circuit element and has a first main surface and a second main surface that face each other. The plate-shaped elastic member extends in a band shape and has elastic force. The first main surface of the electronic component abuts against the heat dissipation member. The second main surface of the electronic component includes a surface of one or more convex portions formed to protrude from the second main surface on the side opposite to the side on which the first main surface is located. The plate-shaped elastic member is fixed to the heat dissipation member with the first main surface of the electronic component pressed against the heat dissipation member by elastic force generated by bending the plate-shaped elastic member abutting against the convex portions.

[0009] The electronic component according to the present disclosure is an electronic component in which an electronic circuit element is sealed by a sealing body. The sealing body has a first main surface and a second main surface. A heat dissipation member is in contact with the first main surface. The second main surface is disposed so as to face the first main surface. A convex portion is formed on the second main surface so as to protrude from the second main surface on the side opposite to the side on which the first main surface is located.

[0010] The circuit board according to the present disclosure has a structure in which the above-described electronic component assembly is mounted on a printed wiring board.

[0011] In the electronic component assembly according to the present disclosure, the plate-shaped elastic member is fixed to the heat dissipation member in a state in which the first main surface of the electronic component is pressed against the heat dissipation member by the elastic force generated by bending the plate-shaped elastic member in contact with the convex portion. This brings the first main surface of the electronic component into close contact with the heat dissipation member. As a result, heat generated by the electronic component can be efficiently conducted to the heat dissipation member and dissipated. Moreover, the elastic force of the plate-shaped elastic member allows for easy heat dissipation.

[0012] In the electronic component according to the present disclosure, the second main surface of the sealing body is formed with a convex portion that protrudes from the second main surface toward the side opposite the first main surface, thereby generating an elastic force in the plate-shaped elastic member, allowing the first main surface of the sealing body to be tightly attached to the heat dissipation member.

[0013] According to the circuit board of the present disclosure, a convex portion is formed on the sealing body of the electronic component of the electronic component assembly mounted on the printed wiring board, thereby generating an elastic force in the plate-shaped elastic member, bringing the first main surface of the sealing body into close contact with the heat dissipation member, and enabling efficient dissipation of heat generated by the electronic component.

[0014] 11 is an exploded perspective view of a circuit board on which an electronic component assembly according to a first embodiment is mounted. FIG. 12 is a perspective view of a circuit board on which an electronic component assembly is mounted in the same embodiment. FIG. 13 is a side view including a partial cross section of a circuit board on which an electronic component assembly is mounted in the same embodiment. FIG. 14 is a first perspective view showing the appearance of an electronic component in the electronic component assembly in the same embodiment. FIG. 15 is a second perspective view showing the appearance of an electronic component in the electronic component assembly in the same embodiment. FIG. 16 is a side view showing a process of attaching a leaf spring in the electronic component assembly to a heat dissipation member in the same embodiment. FIG. 17 is a side view showing a state in which the leaf spring in the electronic component assembly has been attached to the heat dissipation member in the same embodiment. FIG. 18 is a side view of a circuit board on which an electronic component assembly according to a modified example is mounted in the same embodiment. FIG. 19 is a side view of an electronic component assembly according to a second embodiment. FIG. 19 is a perspective view showing the appearance of an electronic component in the electronic component assembly in the same embodiment. FIG. 19 is a cross-sectional view taken along the cross-sectional line XI-XI shown in FIG. 10 in the same embodiment. FIG. 19 is a perspective view showing the appearance of an electronic component in an electronic component assembly according to a modified example in the same embodiment.

[0015] (Introduction) It is known that when electronic components use electrical energy to perform a desired function, the temperature of the electronic components rises due to heat generated by the conversion of a portion of the electrical energy. In particular, power conversion devices that consume high power and integrated circuits with high circuit integration and high operating frequencies generate more heat. As a result, problems such as a decrease in performance or a shortened lifespan of power conversion devices may arise as the temperature rises.

[0016] In order to avoid such problems, it is important to suppress the temperature rise of electronic components by actively releasing the heat generated in power conversion devices, etc. to the outside or by cooling the power conversion devices, etc.

[0017] In order to efficiently dissipate heat generated in electronic components, a heat dissipation member such as a heat sink is generally used. One example of a heat sink is a heat sink with multiple fins. The multiple fins are arranged parallel to each other and spaced apart.

[0018] This type of heat sink is formed by extruding a material that has good thermal conductivity and is easy to process, such as aluminum. By providing multiple fins, the surface area of ​​the heat sink can be increased, allowing heat generated by electronic components to be efficiently dissipated into the air.

[0019] In order to dissipate heat generated in an electronic component from a heat dissipation member such as a heat sink, it is necessary to efficiently conduct the heat generated in the electronic component to the heat dissipation member. To achieve this, it is desirable to increase the contact area between the electronic component and the heat dissipation member.

[0020] If both the contact surface (heat dissipation surface) of the electronic component that comes into contact with the heat dissipation member and the contact surface of the heat dissipation member that comes into contact with the electronic component were ideally flat, it would be possible to achieve perfect adhesion between the two. However, the contact surfaces of the electronic component and the heat dissipation member that come into contact with each other may have small irregularities during processing. Furthermore, warping may occur due to the characteristics of the materials of the electronic component or the heat dissipation member.

[0021] This makes it difficult to bring the contact surfaces of the electronic component and the heat dissipation member into close contact, resulting in gaps between the contact surfaces of the electronic component and the heat dissipation member.If there are many gaps and the contact area between the contact surfaces of the electronic component and the heat dissipation member is small, heat conduction from the electronic component to the heat dissipation member will not be efficient.

[0022] Therefore, a method is adopted in which a material (layer) with relatively high thermal conductivity, such as a thermally conductive sheet, a thermally conductive pad, or silicone grease, is sandwiched between the contact surfaces of the electronic component and the heat dissipation member to fill the gap, thereby enabling efficient heat conduction from the electronic component to the heat dissipation member.

[0023] Such highly thermally conductive materials are called thermal interface materials (hereinafter referred to as "TIMs"). A material softer than the electronic component and the heat dissipation member is used for the TIM in order to absorb the unevenness of the surfaces of the electronic component and the heat dissipation member. Therefore, in order to absorb the unevenness of the respective surfaces and fill the gap, the electronic component and the heat dissipation member are joined by bonding the TIM itself. Alternatively, the TIM is sandwiched between the electronic component and the heat dissipation member and held in a pressure-applied state.

[0024] Common methods for holding an electronic component and a heat dissipation member under pressure include using a spring to apply a constant pressure to the electronic component and heat dissipation member sandwiched between them via a TIM, or using screws tightened to a constant torque to secure the electronic component and heat dissipation member sandwiched between them.

[0025] In particular, in the method of fastening an electronic component to a heat dissipation member with screws, the pressure acting on the electronic component varies greatly depending on the tightening torque, so it is necessary to manage the tightening torque. Managing the tightening torque is cumbersome. In addition, there is a concern that pressure may be concentrated around the screw when the screw is tightened.

[0026] When the screws are tightened with a strong torque, pressure acts locally on the electronic component, the heat dissipation member, and the TIM, which can cause warping (deformation). As a result, the electronic component, the TIM, and the heat dissipation member are in close contact with each other around the screws, but the pressure caused by tightening the screws is weak in areas away from the screws, which could reduce the heat dissipation effect.

[0027] In order to prevent pressure from concentrating around the screws, Patent Document 1 proposes a heat dissipation member (heat sink) with a cross-sectional shape that is convex toward the electronic component. By using such a heat dissipation member, the center of the electronic component, which is far from the screws, is tightly attached to the heat dissipation member by applying strong pressure.

[0028] If the electronic component is relatively hard and does not easily deform when pressure is applied, tightening the screws will deform the heat dissipation member so that its ends approach the electronic component while its center abuts the electronic component, thereby flattening the contact surface of the heat dissipation member that comes into contact with the electronic component and increasing the contact area between the heat dissipation member and the electronic component.

[0029] Generally, electronic components have a structure in which electronic circuit elements are encapsulated in resin (molded), and electronic components are more susceptible to deformation when pressure is applied than heat dissipation members. Therefore, if the heat dissipation member deforms when its center is in contact with the electronic component, the pressure acting on the electronic component may deform the encapsulated electronic circuit elements, wire bonding, or solder joints that electrically connect the electronic circuit elements. As a result, the electronic circuit elements may be destroyed, electrical connections may be impaired, or the reliability of the electronic component may be reduced.

[0030] The electronic component assembly etc. according to the present disclosure has been made to solve these technical problems. Hereinafter, in each embodiment, the electronic component assembly etc. according to the present disclosure will be specifically described.

[0031] First Embodiment. An example of an electronic component assembly according to a first embodiment will be described. As shown in Figures 1, 2, and 3, the electronic component assembly 1 includes an electronic component 3, a heat dissipation member 29, and a leaf spring 31 serving as a plate-shaped elastic member. Here, the electronic component 3 is mounted on a printed wiring board 25 with its leads 23 joined to the printed wiring board 25. The structure in which the electronic component assembly 1 is mounted on the printed wiring board 25 is referred to as a circuit board 5. Note that a heat dissipation fin having a plurality of fins is used as the heat dissipation member 29.

[0032] 4 and 5 , the electronic component 3 includes a sealing body 17 that seals the electronic circuit elements 7 and other components. The sealing body 17 has a first main surface 17a and a second main surface 17b that face each other. The sealing body 17 also has a first side portion 17c and a second side portion 17d that face each other and are spaced apart in one direction. The sealing body 17 also has a third side portion 17e and a fourth side portion 17f that face each other and are spaced apart in another direction that intersects (substantially perpendicular to) the one direction.

[0033] As an example, the electronic component 3 is a surface-mount type small outline package (SOP) with gull-wing type leads 23. The leads 23 protrude from each of the first side 17c and the second side 17d of the electronic component 3 (encapsulant 17). A first lead terminal 23a protrudes from the first side 17c. A second lead terminal 23b protrudes from the second side 17d. The leads 23 do not protrude from the third side 17e and the fourth side 17f of the electronic component 3.

[0034] The first main surface 17a of the electronic component 3 (sealing body 17) abuts against the heat dissipation member 29. The second main surface 17b includes the surface of the protruding portion 19. The protruding portion 19 is formed on the second main surface 17b so as to protrude on the side opposite to the side on which the first main surface 17a is located. The protruding portion 19 is curved so as to straddle between the third side portion 17e and the fourth side portion 17f, from which the leads 23 do not protrude. The protruding portion 19 has a curved surface 21. The protruding portion 19 is formed integrally with the sealing body 17.

[0035] Here, the protrusion 19 may be the same material as the sealing body 17 or a separate material. When the protrusion 19 is a separate material from the sealing body 17, the protrusion 19 and the sealing body 17 are integrally connected by adhesive or fitting. While epoxy resin is generally used as the material for the sealing body 17, a ceramic material with a higher hardness than epoxy resin may also be used. In this case, the elastic force of the leaf spring 31 can more uniformly distribute the pressure acting on the second main surface 17b of the electronic component 3. The elastic force of the leaf spring 31 will be described later. Furthermore, when the protrusion 19 is a separate material from the sealing body 17, even for electronic components 3 with the same sealing shape, protrusions 19 of different shapes can be retrofitted to the sealing body 17 to suit the specifications of the electrical circuit or the heat dissipation member 29.

[0036] 1 , the leaf spring 31 extends in a strip shape. Fixed portions 31a that are fixed to the heat dissipation member 29 are formed on both one and the other sides of the leaf spring 31. A pressure contact portion 31b that abuts against and presses against the protrusion 19 of the electronic component 3 is formed between the fixed portion 31a on one side and the fixed portion 31a on the other side. The leaf spring 31 is fixed to the heat dissipation member 29 with a rivet 35 in a manner that sandwiches the electronic component 3 between the heat dissipation member 29 and the leaf spring 31. The electronic component assembly 1 according to the first embodiment is configured as described above.

[0037] 6 and 7 , in the electronic component assembly 1 described above, when the leaf spring 31 is fixed to the heat dissipation member 29 with the rivet 35, the strip-shaped leaf spring 31 is bent by the protrusion 19 of the electronic component 3. The bending of the leaf spring 31 generates an elastic force in the pressure contact portion 31b, and this elastic force presses the electronic component 3 toward the heat dissipation member 29. As a result, the first main surface 17a of the electronic component 3 comes into close contact with the heat dissipation member 29.

[0038] That is, in the electronic component assembly 1, the leaf spring 31 is fixed to the heat dissipation member 29 in a state in which the first main surface 17a of the electronic component 3 is pressed against the heat dissipation member 29 by the elastic force generated by bending the leaf spring 31 abutting against the protrusion 19. As a result, heat generated from the electronic component 3 can be efficiently conducted to the heat dissipation member 29 and dissipated. Furthermore, the elastic force of the leaf spring 31 can be used to easily dissipate heat.

[0039] For example, consider a case where an electronic circuit element that generates a relatively large amount of heat is sealed near the center of the electronic component 3 (sealing body 17). In this case, the surface of the protrusion 19 that contacts the leaf spring 31 is positioned facing the electronic circuit element, i.e., the protrusion 19 is located in a region that overlaps with the electronic circuit element in a plan view from the second main surface 17b. In this case, the elastic force of the leaf spring 31 acts in a concentrated manner via the protrusion 19 on the electronic circuit element that generates a large amount of heat, allowing the electronic component 3 to be tightly attached to the heat dissipation member 29. This allows the heat generated by the electronic circuit element to be efficiently conducted to the heat dissipation member 29 and dissipated.

[0040] Here, it is assumed that the pressure acting on the protrusion 19 due to the elastic force of the leaf spring 31 is relatively large, and the rigidity of the heat dissipation member 29 is sufficiently large relative to the elastic force of the leaf spring 31 .

[0041] The displacement of the first main surface 17a of the electronic component 3 that contacts the heat dissipation member 29 relative to the heat dissipation member 29 is within the range of the unevenness or warpage occurring on the surfaces of the electronic component 3 and the heat dissipation member 29, respectively, and the shape of the electronic component 3 does not undergo displacement (deformation) beyond that range. Therefore, the contact surface between the first main surface 17a of the electronic component 3 and the heat dissipation member 29 is substantially flat. This makes it possible to prevent the electronic circuit elements or joints of the electronic circuit elements or the like sealed in the sealing body 17 from being damaged or otherwise reduced in reliability as the electronic component 3 due to displacement or deformation of the electronic component 3.

[0042] In the electronic component 3 in the electronic component assembly 1 described above, the convex portion 19 has a curved surface. By bringing the curvature of the curved surface of the convex portion 19 closer to the curvature of the leaf spring 31 that curves due to elastic deformation, the contact area between the electronic component 3 (convex portion 19) and the leaf spring 31 can be expanded. This allows heat generated by the electronic component 3 to be dissipated from the leaf spring 31 as well. By using a material with high thermal conductivity as the material for the leaf spring 31, heat generated by the electronic component 3 can be efficiently dissipated from both the heat dissipation member 29 and the leaf spring 31.

[0043] The curvature of the leaf spring 31, which bends due to elastic deformation, can be designed to an optimal value in advance by adjusting the material, thickness, width, etc. of the leaf spring 31. Furthermore, a step or a spacer member may be interposed between the leaf spring 31 and the heat dissipation member 29. In this case, the curvature of the leaf spring 31 can be adjusted by adjusting the height of the step or the thickness of the spacer member.

[0044] When the curvature of the leaf spring 31 is smaller than the curvature of the protrusion 19 of the electronic component 3, in the above-described electronic component assembly 1, the elastic force of the leaf spring 31 acts on the top of the protrusion 19 located near the longitudinal center of the electronic component 3. Therefore, when an electronic circuit element that generates a relatively large amount of heat is sealed in the longitudinal center of the electronic component 3 (sealing body 17), the generated heat can be efficiently dissipated.

[0045] On the other hand, when the curvature of the leaf spring 31 is approximately the same as or greater than the curvature of the protrusion 19 of the electronic component 3, the elastic force of the leaf spring 31 acts more on both ends of the electronic component 3 than on the center in the longitudinal direction of the electronic component 3. This increases the area where the electronic component 3 and the heat dissipation member 29 are in close contact with each other, thereby promoting heat dissipation.

[0046] Furthermore, if the electronic circuit element sealed in the longitudinal center of the electronic component 3 is susceptible to the compressive stress acting on the sealing body 17 due to the elastic force of the leaf spring 31, the effect of the compressive stress on the electronic circuit element can be suppressed by applying the elastic force of the leaf spring 31 to both end sides of the electronic component 3 rather than near the longitudinal center.

[0047] As described above, in the electronic component assembly 1 described above, when the leaf spring 31 is fixed to the heat dissipation member 29, the leaf spring 31 abuts against the curved convex portion 19 of the electronic component 3, causing the strip-shaped leaf spring 31 to bend. The bending of the leaf spring 31 generates an elastic force in the pressure contact portion 31b, which presses the electronic component 3 toward the heat dissipation member 29. This allows the first main surface 17a of the electronic component 3 to be in close contact with the heat dissipation member 29, and as a result, heat generated from the electronic component 3 can be efficiently conducted to the heat dissipation member 29 and dissipated.

[0048] Furthermore, using a leaf spring 31 that has not been bent has the following advantages. First, consider the case where a leaf spring that has been bent to form an M-shape when viewed from the side as shown in FIG. 3 is used. In this case, although the elastic force of the leaf spring can be applied to the vicinity of the longitudinal center of the electronic component, an additional step of bending the leaf spring is required. Furthermore, it is difficult to process the leaf spring into a shape that will uniformly press against the electronic component 3.

[0049] In contrast, by using the leaf spring 31 that has not been bent, additional processing is not required, and the structure of the electronic component assembly 1 can be simplified compared to when a leaf spring that has been bent is used.

[0050] Furthermore, in the method of pressing the electronic component 3 toward the heat dissipation member 29 using the elastic force of the leaf spring 31, even if a TIM is not interposed between the electronic component 3 and the heat dissipation member 29, the pressing force due to the elastic force of the leaf spring 31 can be applied to the entire contact surface where the electronic component 3 and the heat dissipation member 29 come into contact with each other.

[0051] This reduces gaps between the electronic components 3 and the heat dissipation member 29 caused by unevenness or warping of the electronic components 3 and the heat dissipation member 29, thereby increasing the contact area between the electronic components 3 and the heat dissipation member 29. As a result, this contributes to efficient heat conduction from the electronic components 3 to the heat dissipation member 29.

[0052] In this way, efficient heat conduction from the electronic component 3 to the heat dissipation member 29 eliminates the need to interpose a TIM between the electronic component 3 and the heat dissipation member 29, but a TIM may be interposed. Interposing a TIM can further increase the contact area between the electronic component 3 and the heat dissipation member 29, contributing to more efficient heat conduction from the electronic component 3 to the heat dissipation member 29. Note that Figure 1 and other figures show an electronic component assembly 1 without an interposed TIM.

[0053] The electronic component 3 in the electronic component assembly 1 described above has been described as an example of a small outline package. The electronic component 3 is not limited to a small outline package, and may be, for example, a dual in-line package (DIP). A dual in-line package is a package in which the leads of the electronic component are inserted into through holes in a printed wiring board and soldered. The electronic component 3 used in the electronic component assembly 1 does not depend on the electrode structure, such as the shape and number of leads 23.

[0054] Furthermore, the above-described circuit board 5, in which the electronic component assembly 1 is mounted on the printed wiring board 25, has been described by taking as an example the printed wiring board 25 having the leaf spring mounting holes 27 formed therein for mounting the electronic component assembly 1. As shown in Figure 8, a printed wiring board 25 without the leaf spring mounting holes formed therein can also be used, provided that the length of the leads 23 is relatively long and a sufficient gap can be secured between the electronic component 3 and the printed wiring board 25 for mounting the leaf springs 31.

[0055] Second Embodiment An electronic component assembly and the like according to a second embodiment will be described. Here, an example of an electronic component assembly including an electronic component 3 on which a plurality of protrusions 19 are formed will be described.

[0056] 9 and 10 , the second main surface 17b of the electronic component 3 has a dome-shaped protrusion 19 formed thereon, which is a portion of a sphere cut away. The protrusion 19 has a curved surface 21 that includes a portion of the spherical surface. The protrusion 19 includes a first protrusion 19a and a second protrusion 19b. The second main surface 17b includes a surface of the first protrusion 19a and a surface of the second protrusion 19b. The protrusion 19 is formed integrally with the sealing body 17.

[0057] A TIM (not shown) is interposed between the electronic component 3 and the heat dissipation member 29. Other configurations are similar to those of the electronic component assembly 1 shown in Fig. 1 and the like, and therefore the same members are given the same reference numerals, and the description thereof will not be repeated unless necessary.

[0058] In the electronic component assembly 1, the first convex portion 19a and the second convex portion 19b are each formed at a position corresponding to the electronic circuit element 7 that generates a relatively large amount of heat. Here, as shown in Fig. 11 , when the electronic circuit element 7 sealed in the sealing body 17 includes a first electronic circuit element 7a, a second electronic circuit element 7b, and a third electronic circuit element 7c, for example, the first heat generation amount of the first electronic circuit element 7a is greater than the second heat generation amount of the second electronic circuit element 7b or the third electronic circuit element 7c.

[0059] The first electronic circuit element 7a and the second electronic circuit element 7b are joined to the first lead frame 11a of the lead frame 11. The third electronic circuit element 7c is joined to the second lead frame 11b of the lead frame 11 by a solder fillet 13. The second electronic circuit element 7b and the second lead frame 11b are electrically connected by a bonding wire 15.

[0060] In this case, the first protrusion 19a is formed on the second main surface 17b at a position facing the first electronic circuit element 7a. Similarly, the second protrusion 19b is formed at a position facing an electronic circuit element (not shown) that generates a relatively large amount of heat.

[0061] 9 , by fixing the leaf spring 31 to the heat dissipation member 29 with the rivets 35, the strip-shaped leaf spring 31 is curved by the first convex portion 19 a and the second convex portion 19 b of the electronic component 3. The bending of the leaf spring 31 generates an elastic force in the pressure contact portion 31 b (see FIG. 1 ), and the elastic force presses the electronic component 3 toward the heat dissipation member 29.

[0062] The first convex portions 19a and the second convex portions 19b are each formed at a position on the second main surface 17b facing the electronic circuit elements 7a, etc., which generate a large amount of heat. This allows the portion of the first main surface 17a facing the electronic circuit elements 7a, etc., which generate a large amount of heat, to be closely attached to the heat dissipation member 29. As a result, the heat generated from the electronic circuit elements 7a, etc., can be efficiently conducted to the heat dissipation member 29 and dissipated.

[0063] It is desirable to form the convex portion 19 in consideration of the effect of the compressive stress acting on the sealing body 17 due to the elastic force of the leaf spring 31. If, for example, the second electronic circuit element 7b among the electronic circuit elements 7 sealed in the sealing body 17 is susceptible to the effect of the compressive stress acting on the sealing body 17 due to the elastic force of the leaf spring 31, it is desirable to arrange the convex portion 19 so as to avoid the position on the second main surface 17b facing the second electronic circuit element 7b.

[0064] Furthermore, for example, if the bonding wire 15 electrically connected to the second electronic circuit element 7 b is susceptible to the compressive stress acting on the sealing body 17, it is desirable to arrange the convex portion 19 so as to avoid the position on the second main surface 17 b that faces the bonding wire 15. Furthermore, for example, if the solder fillet 13 that joins the third electronic circuit element 7 c to the second lead frame 11 b is susceptible to the compressive stress acting on the sealing body 17, it is desirable to arrange the convex portion 19 so as to avoid the position on the second main surface 17 b that faces the solder fillet 13.

[0065] In general, it is difficult to confirm the internal structure of an electronic component 3 from its appearance. Electronic components 3 having various shapes have different positions of the electronic circuit elements 7 in the electronic component 3. Furthermore, the electrical connection structures also differ. For this reason, it is more efficient and desirable for the developer of the electronic component 3, who is familiar with the internal structure of the electronic component 3, to set the position (arrangement) of the convex portion 19 on the second main surface 17b of the electronic component 3 when designing the electronic component 3, rather than for the manufacturer who purchases the electronic component 3 to set the position.

[0066] The convex portion 19 formed on the electronic component 3 in the electronic component assembly 1 described above is formed in a dome shape having a part of a spherical surface that resembles a part of a sphere cut away, which has the following advantages.

[0067] When the leaf spring 31 is elastically deformed, it may be difficult for the curvature of the leaf spring 31 to be as designed. In this case, if the curvature of a part of the spherical surface of the convex portion 19 becomes larger than the curvature of the curved surface of the elastically deformed leaf spring 31, the leaf spring 31 will come into contact with any part of the surface of the dome-shaped convex portion 19 (part of the spherical surface) excluding the apex.

[0068] Therefore, the elastic force of the leaf spring 31 in contact with the surface of the protrusion 19 is dispersed over the entire dome-shaped protrusion 19. As a result, even if the curvature of the leaf spring 31 differs from the curvature of the surface of the protrusion 19, the leaf spring 31 presses the electronic component 3 against the heat dissipation member 29, allowing the electronic component 3 to be tightly attached to the heat dissipation member 29.

[0069] The above-described electronic component assembly 1 has been described as an example in which the first convex portion 19a and the second convex portion 19b are formed as the convex portion 19. As shown in Fig. 12, it is desirable for the electronic component assembly 1 to further include, for example, a third convex portion 19c and a fourth convex portion 19d, so that the multiple convex portions 19 are arranged at a distance from each other in a balanced manner on the second main surface of the electronic component 3. This makes it possible to increase the area of ​​substantial contact over the entire contact surface between the first main surface 17a of the electronic component 3 and the heat dissipation member 29.

[0070] Furthermore, in the electronic component assembly 1 according to each embodiment, the protrusion 19 having the curved surface 21 has been described as an example, but the present invention is not limited to the protrusion 19 having a curved surface as long as the leaf spring 31 can be curved to apply an appropriate pressing force to the appropriate location on the electronic component 3.

[0071] Furthermore, although the protrusion 19 has been described as being formed integrally with the plug 17, the protrusion 19 may be formed as a separate body from the plug 17. By joining a separate protrusion to the second main surface 17b of the plug 17, the desired effect can be obtained.

[0072] In addition, in the electronic component assembly 1 according to each embodiment, the leaf spring 31 is fixed to the heat dissipation member 29 by the rivet 35. The method for fixing the leaf spring 31 to the heat dissipation member 29 is not limited to the rivet 35, as long as excessive pressure is not applied to the electronic component 3.

[0073] The electronic component assemblies and the like described in the respective embodiments can be combined in various ways as required.

[0074] The embodiments disclosed herein are examples and are not intended to be limiting. The scope of the present disclosure is defined by the scope of the claims, not the scope described above, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

[0075] The present disclosure includes the following aspects: [Supplementary Note 1] An electronic component assembly comprising: a heat dissipation member; an electronic component including a sealing body that seals an electronic circuit element and has first and second main surfaces facing each other; and a plate-shaped elastic member that extends in a band shape and has elasticity, wherein the first main surface of the electronic component abuts against the heat dissipation member, and the second main surface of the electronic component includes a surface of one or more convex portions formed to protrude from the second main surface on an opposite side to a side on which the first main surface is located, and the plate-shaped elastic member is fixed to the heat dissipation member in a state in which the first main surface of the electronic component is pressed against the heat dissipation member by the elastic force generated by bending the plate-shaped elastic member abutting against the convex portions.

[0076] [Supplementary Note 2] The plate-shaped elastic member includes: a first fixing portion formed on one side of the plate-shaped elastic member extending in a band shape and fixed to the heat dissipation member; a second fixing portion formed on the other side of the plate-shaped elastic member extending in a band shape and fixed to the heat dissipation member; and a pressure-contact portion located between the first fixing portion and the second fixing portion and abutting against the electronic component, wherein the pressure-contact portion is curved by fixing each of the first fixing portion and the second fixing portion to the heat dissipation member, and the first main surface of the electronic component is pressed against the heat dissipation member by the elastic force generated in the pressure-contact portion as a result of the pressure-contact portion being curved.

[0077] [Supplementary Note 3] The electronic component assembly according to Supplementary Note 1 or 2, wherein the protrusion is formed integrally with the sealing body.

[0078] [Supplementary Note 4] The electronic component assembly according to any one of Supplementary Notes 1 to 3, wherein the convex portion has a curved surface, and the plate-shaped elastic member includes a portion that curves along the curved surface.

[0079] [Supplementary Note 5] The electronic component assembly according to Supplementary Note 1, wherein the protrusion includes a first protrusion and a second protrusion.

[0080] [Supplementary Note 6] The electronic component assembly according to Supplementary Note 5, wherein the electronic circuit elements include a first electronic circuit element that generates a first amount of heat during operation, and a second electronic circuit element that generates a second amount of heat during the operation, the first amount of heat generation being higher than the second amount of heat generation, and the first convex portion is disposed at a position on the second main surface that faces the first electronic circuit element.

[0081] [Supplementary Note 7] The electronic component assembly according to Supplementary Note 5, wherein each of the first convex portion and the second convex portion has the surface that is a part of a spherical surface.

[0082] [Appendix 8] The electronic component assembly according to any one of Appendices 1 to 7, wherein the sealing body includes first and second side portions facing each other and from which lead terminals protrude, and third and fourth side portions facing each other and from which the lead terminals do not protrude, and the plate-shaped elastic member is disposed so as to straddle the space between the third side portion and the fourth side portion.

[0083] [Supplementary Note 9] The electronic component assembly according to any one of Supplementary Notes 1 to 8, wherein the heat dissipation member includes a heat dissipation fin.

[0084] [Appendix 10] An electronic component in which an electronic circuit element is sealed with a sealing body, the sealing body comprising: a first main surface with which a heat dissipation member comes into contact; and a second main surface disposed to face the first main surface; and a convex portion formed on the second main surface so as to protrude toward the side opposite to the side on which the first main surface is located with respect to the second main surface.

[0085] [Supplementary Note 11] A circuit board in which the electronic component assembly according to any one of Supplementary Notes 1 to 9 is mounted on a printed wiring board.

[0086] [Appendix 12] The circuit board according to Appendix 11, wherein the printed wiring board has a mounting hole formed in an area where the electronic component assembly is mounted, for mounting the electronic component assembly, in such a manner that the plate-shaped elastic member is exposed from the side opposite to the side where the electronic component assembly is mounted.

[0087] The present disclosure is effectively applied to an electronic component assembly including an electronic component and a heat dissipation member.

[0088] 1 Electronic component assembly, 3 Electronic component, 5 Circuit board, 7 Electronic circuit element, 7a First electronic circuit element, 7b Second electronic circuit element, 7c Third electronic circuit element, 11 Lead frame, 11a First lead frame, 11b Second lead frame, 13 Solder fillet, 15 Wire, 17 Sealant, 17a First main surface, 17b Second main surface, 17c First side portion, 17d Second side portion, 17e Third side portion, 17f Fourth side portion, 19 Convex portion, 19a First convex portion, 19b Second convex portion, 19c Third convex portion, 19d Fourth convex portion, 21 Curved surface, 23 Lead, 23a First lead terminal, 23b Second lead terminal, 25 Printed wiring board, 27 Leaf spring mounting hole, 29 Heat dissipation member, 31 Leaf spring, 31a Fixing portion, 31b Pressure welded part, 35 rivets.

Claims

1. An electronic component assembly comprising: a heat dissipation member; an electronic component including an encapsulant that seals an electronic circuit element and has first and second main surfaces facing each other; and a plate-shaped elastic member that extends in a band shape and has elasticity, wherein the first main surface of the electronic component abuts against the heat dissipation member, and the second main surface of the electronic component includes one or more convex surfaces formed to protrude from the second main surface on the side opposite to the side on which the first main surface is located, and the plate-shaped elastic member is fixed to the heat dissipation member in a state in which the first main surface of the electronic component is pressed against the heat dissipation member by the elastic force generated by bending the plate-shaped elastic member abutting against the convex surfaces.

2. An electronic component assembly as claimed in claim 1, wherein the plate-shaped elastic member includes: a first fixing portion formed on one side of the plate-shaped elastic member extending in a band-like shape and fixed to the heat dissipation member; a second fixing portion formed on the other side of the plate-shaped elastic member extending in a band-like shape and fixed to the heat dissipation member; and a pressure contact portion located between the first fixing portion and the second fixing portion and abutting against the electronic component, wherein the pressure contact portion is curved by fixing each of the first fixing portion and the second fixing portion to the heat dissipation member, and the first main surface of the electronic component is pressed against the heat dissipation member by the elastic force generated in the pressure contact portion as a result of the pressure contact portion being curved.

3. An electronic component assembly according to claim 1 or 2, wherein the protrusion is formed integrally with the sealing body.

4. An electronic component assembly according to any one of claims 1 to 3, wherein the convex portion has a curved surface, and the plate-shaped elastic member includes a portion that curves along the curved surface.

5. The electronic component assembly according to claim 1, wherein said protrusions include a first protrusion and a second protrusion.

6. An electronic component assembly as claimed in claim 5, wherein the electronic circuit elements include a first electronic circuit element that generates a first amount of heat during operation, and a second electronic circuit element that generates a second amount of heat during said operation, the first amount of heat being higher than the second amount of heat, and the first convex portion is arranged at a position on the second main surface facing the first electronic circuit element.

7. An electronic component assembly according to claim 5, wherein each of said first and second protrusions has a surface that is a portion of a sphere.

8. An electronic component assembly according to any one of claims 1 to 7, wherein the sealing body includes first and second side portions facing each other and from which lead terminals each protrude, and third and fourth side portions facing each other and from which the lead terminals each do not protrude, and the plate-like elastic member is arranged so as to straddle the space between the third side portion and the fourth side portion.

9. An electronic component assembly according to any one of claims 1 to 8, wherein the heat dissipation member includes a heat dissipation fin.

10. An electronic component in which an electronic circuit element is sealed with a sealing body, the sealing body having a first main surface against which a heat dissipation member comes into contact, and a second main surface arranged to face the first main surface, and a convex portion formed on the second main surface so as to protrude on the side opposite to the side on which the first main surface is located relative to the second main surface.

11. A circuit board comprising an electronic component assembly according to any one of claims 1 to 9 mounted on a printed wiring board.

12. A circuit board as claimed in claim 11, wherein the printed wiring board has a mounting hole formed in the area where the electronic component assembly is mounted, for mounting the electronic component assembly, in such a manner that the plate-shaped elastic member is exposed from the side opposite to the side where the electronic component assembly is mounted.

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