Electronic device

Abstract

To provide an electronic device capable of preventing underfill from adhering to a component to be protected requiring no special processing.SOLUTION: An electronic device 100 includes: a wiring circuit board 10; a target electronic component mounted on the wiring circuit board 20; an underfill 50 formed in a gap between at least the wiring circuit board and the target electronic component; and a protection electronic component 30 mounted on the wiring circuit board. The electronic device further includes suction electronic components 41, 42 that are mounted on the wiring circuit board so as to suck the underfill. At least part of the suction electronic component is placed in a second application area CA2 where the underfill spreads around the target electronic component.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to electronic devices. [Background technology]

[0002] Patent Document 1 discloses an electronic device. The electronic device includes a protection target portion formed on a substrate to be protected from underfill inflow, and an underfill inflow prevention portion formed on the substrate so as to surround all or part of the protection target component. In the electronic device, the underfill inflow prevention portion is provided in the substrate with a concave groove or a convex wall. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-192442 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in electronic devices, there is a risk that the underfill may reach the components to be protected by crossing the grooves or walls, and further, special processing is required to form the grooves or walls on the substrate.

[0005] One disclosed object is to provide an electronic device that can suppress adhesion of underfill to components to be protected without requiring special processing. [Means for solving the problem]

[0006] The electronic device disclosed herein comprises: A wiring board (10), a first electronic component (20) mounted on a wiring board; an underfill (50) provided in at least a gap between the wiring board and the first electronic component; a second electronic component (30) mounted on the wiring board and to be protected from adhesion of underfill; a third electronic component (41-44) mounted on the wiring board and capable of adsorbing underfill; At least a portion of the third electronic component is disposed in a region around the first electronic component where the underfill spreads and wets the first electronic component.

[0007] In this way, in the electronic device, at least a portion of the third electronic component is disposed in the application area around the first electronic component where the underfill spreads. Therefore, in the electronic device, the third electronic component can absorb the underfill that spreads through the gap between the wiring board and the first electronic component. Therefore, the electronic device does not require special processing to provide walls or grooves, and can prevent the spread underfill from adhering to the second electronic component.

[0008] The various aspects disclosed in this specification employ different technical means to achieve their respective objectives. The reference numerals in parentheses in the claims and in this section are intended to exemplify correspondences with the following embodiments and are not intended to limit the technical scope. The objectives, features, and advantages disclosed in this specification will become more apparent by reference to the following detailed description and the accompanying drawings. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a plan view showing a schematic configuration of an electronic device according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 10 is a plan view showing a schematic configuration of an electronic device according to a first modified example. [Figure 4] FIG. 10 is a plan view showing a schematic configuration of an electronic device according to a second modification. [Figure 5] FIG. 11 is a plan view showing a schematic configuration of an electronic device according to a third modification. [Figure 6] FIG. 10 is a plan view showing a schematic configuration of an electronic device according to a fourth modification. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, several embodiments for carrying out the present disclosure will be described with reference to the drawings. In each embodiment, parts corresponding to matters described in the preceding embodiment may be assigned the same reference numerals, and duplicated explanations may be omitted. In each embodiment, when only a part of the configuration is described, the other parts of the configuration may be applied by referring to the other embodiment described previously.

[0011] In the following description, the three mutually orthogonal directions are referred to as the X direction, the Y direction, and the Z direction. Also, for example, the plane defined by the X direction and the Y direction can be referred to as the XY plane.

[0012] (Embodiment) An electronic device 100 of this embodiment will be described with reference to Figures 1 and 2. The electronic device 100 includes a wiring board 10, electronic components 20, 30, 41, and 42, and an underfill 50. The electronic device 100 also includes solder 60 that connects the wiring board 10 and the electronic components 20, 30, 41, and 42. The electronic device 100 may include a conductive adhesive instead of the solder 60. In other words, the electronic device 100 can be said to include a conductive connecting member such as the solder 60 or silver paste.

[0013] In the electronic device 100, electronic components 20, 30, 41, and 42 are electrically connected via wiring 12 on a wiring board 10. The electronic device 100 can be used, for example, as an electronic control device that outputs a control signal to a device to be controlled. The electronic control device is configured to be mountable on, for example, a mobile object. Examples of the mobile object include vehicles such as electric cars, hybrid cars, and fuel cell cars, flying objects such as electric vertical take-off and landing aircraft and drones, ships, construction machinery, and agricultural machinery. However, the electronic device 100 is not limited to these.

[0014] <Wiring board> As shown in FIGS. 1 and 2, wiring board 10 includes an electrically insulating insulating substrate 11 made of resin or the like, and conductive wiring 12 made of copper foil or the like. Insulating substrate 11 has one surface S1 and a back surface S2 opposite to surface S1. Wiring 12 is provided, for example, on surface S1 of insulating substrate 11. Wiring 12 may also be provided inside insulating substrate 11. In other words, wiring board 10 may be a multilayer substrate in which wiring 12 is stacked with insulating substrate 11 interposed therebetween.

[0015] A pad 13 is formed on a part of the wiring 12. The pad 13 is a portion to which an electrode 22 of the electronic components 20, 30, 41, 42 is connected. The pad 13 is electrically connected to the electrode 22 via solder 60.

[0016] FIG. 1 shows a first application area CA1 related to the underfill 50, which will be described later, and a second application area CA2 surrounding the first application area CA1. The first application area CA1 is the area where the underfill 50 is applied. The underfill 50 is formed in the first application area CA1. The first application area CA1 can also be referred to as the area to be applied. Note that hatching is used in FIG. 1 and other figures to distinguish the underfill 50 from other components.

[0017] 1, the first application area CA1 is illustrated around the electronic component 20. However, the first application area CA1 substantially coincides with the facing area of ​​the electronic component 20 in the Z direction.

[0018] The second application area CA2 is an area set around the target electronic component 20. The second application area CA2 is an area where the underfill 50 may wet and spread from the first application area CA1. Therefore, the second application area CA2 may include an area where the underfill 50 is applied and an area where the underfill 50 is not applied. The second application area CA2 corresponds to a coating area. The second application area CA2 can also be called an excess coating area or a virtual coating area.

[0019] The second application area CA2 can be determined through experiments, simulations, etc. The second application area CA2 varies depending on material conditions such as the viscosity and amount of underfill 50, and processing conditions such as the flow rate and force when applying underfill 50. Furthermore, the second application area CA2 is an area where the underfill 50 will not adversely affect the electronic device 100 even if it wets and spreads.

[0020] However, depending on the processing conditions, the underfill 50 may spread outside the second application area CA2. For example, if the underfill 50 spreads within the second application area CA2 and comes into contact with the protective electronic component 30, the underfill 50 may be attracted to the protective electronic component 30 due to the surface tension of the underfill 50. The protective electronic component 30 will be described later.

[0021] <Electronic components> As shown in FIGS. 1 and 2, electronic components 20, 30, 41, and 42 are mounted on a wiring board 10. The electronic components 20, 30, 41, and 42 are circuit elements that, together with wiring 12, form an electronic circuit. The electronic components 20, 30, 41, and 42 may be semiconductor elements, coils, resistor elements, capacitor elements, or the like. As shown in FIG. 1, an electronic device 100 includes, as electronic components, a target electronic component 20, a protection electronic component 30, and attraction electronic components 41 and 42. Note that the number of target electronic components 20, protection electronic components 30, and attraction electronic components 41 and 42 is not particularly limited.

[0022] 1 and 2, the target electronic component 20 is an electronic component in which an underfill 50 is provided between the electronic component 20 and the wiring board 10. In other words, the target electronic component 20 is a target for forming the underfill 50. In this embodiment, a coil is used as an example of the target electronic component 20.

[0023] The target electronic component 20 includes a main body 21 and electrodes 22 provided on a mounting surface S11 of the main body 21. The target electronic component 20 is mounted on the wiring board 10 so that the mounting surface S11 faces the first surface S1. The electrodes 22 are electrically connected to the pads 13 via solder 60. The target electronic component 20 corresponds to the first electronic component.

[0024] The underfill 50 is provided at least in the gap between the wiring board 10 and the target electronic component 20, i.e., in the first application area CA1. As described above, the underfill 50 may be provided in the second application area CA2 in addition to the first application area CA1. As shown in FIG. 1, this embodiment employs an example in which the underfill 50 is provided in part of the second application area CA2.

[0025] The protective electronic component 30 is an electronic component to which it is undesirable for the underfill 50 to adhere. The protective electronic component 30 is, for example, an electronic component whose durability is reduced by the adhesion of the underfill 50. The protective electronic component 30 is an electronic component that is to be protected so that the underfill 50 does not adhere. The protective electronic component 30 can also be said to be a component to be protected. In this way, the protective electronic component 30 is an electronic component that should be protected from the adhesion of the underfill. The protective electronic component 30 corresponds to the second electronic component.

[0026] The protective electronic component 30 is mounted on the wiring board 10 so as to face the surface S1, similar to the target electronic component 20. The electrodes of the protective electronic component 30 are electrically connected to the pads via solder. The protective electronic component 30 is preferably disposed outside the second application area CA2. However, depending on the mounting constraints of the wiring board 10, at least a portion of the protective electronic component 30 may be disposed within the second application area CA2.

[0027] The adsorbable electronic components 41 and 42 are electronic components that can adsorb the underfill 50. In other words, the adsorbable electronic components 41 and 42 are electronic components whose performance does not deteriorate even when the underfill 50 adheres to them. Furthermore, the adsorbable electronic components 41 and 42 can be said to be electronic components that are resistant to the underfill 50. Furthermore, the adsorbable electronic components 41 and 42 can be said to be electronic components that are not affected even when the underfill 50 adheres to them.

[0028] When the underfill 50 comes into contact with the attracted electronic components 41, 42, the underfill 50 is attracted to the attracted electronic components 41, 42 due to the surface tension of the underfill 50. In other words, when the underfill 50 comes into contact with the attracted electronic components 41, 42, it is attracted to the electronic components 41, 42. By attracting the underfill 50, the attracted electronic components 41, 42 prevent the underfill 50 from adhering to the protective electronic component 30. In other words, the attracted electronic components 41, 42 attract the underfill 50 to themselves, thereby preventing the underfill 50 from reaching the protective electronic component 30. The attracted electronic components 41, 42 correspond to third electronic components.

[0029] Resistor elements, capacitor elements, etc. can be used as the adsorbed electronic components 41, 42. As the adsorbed electronic components 41, 42 are electronic components, they are thicker than the wiring 12. However, the adsorbed electronic components 41, 42 are not limited to resistor elements or capacitor elements. The adsorbed electronic components 41 and 42 may be electronic components having different functions, or may be electronic components having the same function. The same applies to the adsorbed electronic components 43, 44, which will be described later. The arrangement of the adsorbed electronic components 41, 42 and the adsorption of the underfill 50 will be described later.

[0030] The suction electronic components 41 and 42 are mounted on the wiring board 10 so as to face the surface S1, similar to the target electronic component 20. The electrodes of the protection electronic component 30 are electrically connected to the pads via solder. Thus, two suction electronic components 41 and 42 are mounted on the wiring board 10. In this embodiment, as an example, two suction electronic components 41 and 42 are used. However, the present disclosure is only required to include at least one suction electronic component.

[0031] As described above, the suction electronic components 41 and 42 are circuit elements that constitute an electronic circuit. That is, the suction electronic components 41 and 42 are not provided solely for the purpose of preventing the underfill 50 from adhering to the protective electronic component 30. In other words, the suction electronic components 41 and 42 are not provided solely for the purpose of protecting the protective electronic component 30 from the underfill 50.

[0032] The distance between the attracted electronic components 41, 42 and the target electronic component 20 is preferably narrower than the distance between the protection electronic component 30 and the target electronic component 20. In other words, the shortest distance between the attracted electronic components 41, 42 and the target electronic component 20 is preferably shorter than the shortest distance between the protection electronic component 30 and the target electronic component 20.

[0033] <Electronic equipment> 1 and 2, the electronic device 100 will be described. The arrangement of the adsorbed electronic components 41 and 42 and the adsorption of the underfill 50 will also be described. The electronic device 100 includes the wiring board 10, electronic components 20, 30, 41, and 42, underfill 50, and solder 60 configured as described above.

[0034] 1, at least a portion of the attracted electronic component 41 is disposed in the second application area CA2, and similarly, at least a portion of the attracted electronic component 42 is disposed in the second application area CA2.

[0035] The attracted electronic components 41 and 42 are arranged adjacent to the target electronic component 20. More specifically, the attracted electronic component 41 is arranged so that its first side wall 41a faces the side wall 20a of the target electronic component 20. The attracted electronic component 42 is arranged so that its first side wall 42a faces the side wall 20a of the target electronic component 20.

[0036] The attracted electronic component 41 is disposed adjacent to the attracted electronic component 42. More specifically, the attracted electronic component 41 is disposed so that the third side wall 41c faces the second side wall 42b of the attracted electronic component 42. In this manner, the two attracted electronic components 41, 42 are disposed parallel to the side wall 20a of the target electronic component 20. Note that, in the present disclosure, three or more attracted electronic components 41, 42 may be disposed parallel to the side wall 20a of the target electronic component 20.

[0037] As described above, the attracted electronic components 41, 42 are arranged in the second application area CA2. Therefore, the attracted electronic components 41, 42 may come into contact with the wet and spread underfill 50. The attracted electronic components 41, 42 then adsorb the wet and spread underfill 50 in the second application area CA2 due to surface tension. In other words, the attracted electronic components 41, 42 are arranged so as to actively attract the underfill 50.

[0038] 1, the underfill 50 adheres to the first side wall 41a, the second side wall 41b, the third side wall 41c, etc. of the adsorbed electronic component 41. The underfill 50 also adheres to the first side wall 42a, the second side wall 42b, the third side wall 42c, etc. of the adsorbed electronic component 42. In other words, the underfill 50 also enters the gap between the adsorbed electronic components 41 and 42.

[0039] 2, when the underfill 50 comes into contact with, for example, the first side wall 41a of the chucked electronic component 41, a fillet-shaped contact portion 50f is formed along the first side wall 41a. The contact portion 50f is also formed corresponding to the other side walls (such as the first side wall 42a). The contact portion 50f can also be considered a raised portion along the first side wall 41a.

[0040] In this way, the adsorbed electronic components 41, 42 are in contact with the underfill 50. However, the adsorbed electronic components 41, 42 may not be in contact with the underfill 50 depending on the material conditions and processing conditions of the underfill 50. Note that in this embodiment, as an example, an example is adopted in which the underfill 50 is not attached to the third side wall 43c.

[0041] <Effects> In this way, in the electronic device 100, at least a portion of the adsorbed electronic components 41, 42 is disposed in the second application area CA2. Therefore, in the electronic device 100, the adsorbed electronic components 41, 42 can adsorb the underfill 50 that wets and spreads from the gap between the wiring board 10 and the target electronic component 20. The adsorbed electronic components 41, 42, together with the target electronic component 20 and the protective electronic component 30, constitute an electronic circuit. Therefore, the electronic device 100 does not require special processing for providing walls or grooves, and can prevent the wet and spread underfill 50 from adhering to the protective electronic component 30.

[0042] Furthermore, the adsorbed electronic components 41, 42 prevent the underfill 50 from adhering to the protective electronic component 30 by adsorption. Therefore, the adsorbed electronic components 41, 42 do not need to be disposed between the target electronic component 20 and the protective electronic component 30. Therefore, the electronic device 100 has improved freedom in arranging the adsorbed electronic components 41, 42.

[0043] Furthermore, the electronic device 100 has two suction electronic components 41, 42 arranged side by side. Therefore, the electronic device 100 can absorb a larger amount of underfill 50 than a configuration having one suction electronic component. Therefore, the electronic device 100 can prevent the underfill 50 from adhering to the protective electronic component 30 more effectively than a configuration having one suction electronic component.

[0044] Incidentally, it is conceivable to form walls for preventing adhesion of the underfill 50 using resist or the like. Grooves for preventing adhesion of the underfill 50 are provided in the wiring board 10. However, there is a possibility that the underfill 50 will climb over the resist walls. Also, there is a possibility that the underfill 50 will overflow the grooves provided in the wiring board 10. Therefore, walls and grooves cannot sufficiently prevent the underfill 50 from adhering to the protective electronic component 30.

[0045] On the other hand, the electronic device 100 adsorbs the underfill 50 to the adsorbed electronic components 41 and 42. Therefore, the electronic device 100 can easily prevent the underfill 50 from passing over the adsorbed electronic components 41 and 42 and reaching the protective electronic component 30.

[0046] Furthermore, when walls or grooves are provided, the size of the wiring board 10 increases by the size of the walls or grooves. However, the electronic device 100 suppresses the suction of the underfill 50 by the suction electronic components 41, 42 that constitute the electronic circuit. Therefore, the electronic device 100 can suppress the suction of the underfill 50 without increasing the size of the wiring board 10.

[0047] The preferred embodiments of the present disclosure have been described above. However, the present disclosure is not limited to the above embodiments, and various modifications are possible within the scope of the present disclosure. Modifications 1 to 4 will be described below as other aspects of the present disclosure. The above embodiments and modifications 1 to 4 can be implemented independently, or can be implemented in appropriate combinations. The present disclosure is not limited to the combinations shown in the embodiments, and can be implemented in various combinations.

[0048] (Variation 1) 3, the electronic device 101 of the first modification example differs from the electronic device 100 in that it includes a guide portion 70. That is, the electronic device 101 has a configuration in which the guide portion 70 is provided in the electronic device 100. The guide portion 70 is a member for guiding the underfill 50 that has wetted and spread in the second application area CA2 to the adsorbed electronic components 41, 42.

[0049] The induction portion 70 is provided on one surface S1 of the wiring board 10. The induction portion 70 is formed, for example, of a conductive wiring pattern. The wiring pattern is a part of the wiring 12. Note that the induction portion 70 may be formed of the wiring pattern and a protective film provided so as to cover the wiring pattern.

[0050] The induction portion 70 is disposed between the target electronic component 20 and the protection electronic component 30. At least a portion of the induction portion 70 is disposed in the second application area CA2. The induction portion 70 has a first portion 71 and a second portion 72 continuing from the first portion 71. The induction portion 70 also has the first portion 71 and the second portion 72 facing each of the two side walls 20a, 20b that are connected to the target electronic component 20 via a corner.

[0051] The first portion 71 is provided along the X direction. The first portion 71 faces the side wall 20b. The second portion 72 is provided along the Y direction. The second portion 72 faces the side wall 20a. The first portion 71 extends from a region where the side wall 20b faces in the Y direction to a region where the adsorbed electronic components 41, 42 face in the Y direction. The second portion 72 extends from an end of the first portion 71 toward the adsorbed electronic components 41, 42. It is preferable that the distance between the second portion 72 and the adsorbed electronic components 41, 42 is narrow.

[0052] The electronic device 101 includes a guide portion 70. Therefore, the electronic device 101 can guide the underfill 50 that has reached the guide portion 70 toward the adsorbed electronic components 41, 42. In other words, the underfill 50 that has reached the guide portion 70 easily spreads along the guide portion 70 onto the adsorbed electronic components 41, 42. Therefore, the electronic device 101 can prevent the underfill 50 from adhering to the protective electronic component 30 more effectively than the electronic device 100.

[0053] The guiding portion 70 may be linear or curved. The guiding portion 70 may be formed of resist, etc. The guiding portion 70 can also be applied to the second and fourth modified examples.

[0054] (Variation 2) 4, the electronic device 102 of the second modification is different from the electronic device 100 in the configuration of the attractable electronic components 41 to 44. The electronic device 102 includes four attractable electronic components 41 to 44. Each of the attractable electronic components 41 to 44 corresponds to a third electronic component.

[0055] The attracted electronic components 41 to 43 are arranged parallel to the sidewall 20a of the target electronic component 20. The attracted electronic components 42 and 44 are arranged perpendicular to the sidewall 20a of the target electronic component 20. The attracted electronic components 41 to 43 are arranged side by side in the Y direction. On the other hand, the attracted electronic components 42 and 44 are arranged side by side in the X direction.

[0056] The adsorbed electronic components 41 to 43 may be positioned differently from one another in the X direction, and the adsorbed electronic components 42 and 44 may be positioned differently from one another in the Y direction.

[0057] The electronic device 102 has three adsorbed electronic components 41 to 43 arranged side by side, and therefore can adsorb a greater amount of underfill 50 than the electronic device 100. Similarly, the electronic device 102 has two adsorbed electronic components 42, 44 arranged side by side, and therefore can adsorb a greater amount of underfill 50 than the electronic device 100. Furthermore, the electronic device 102 can increase the gaps between the adsorbed electronic components 41 to 43, and therefore can adsorb a greater amount of underfill 50 than the electronic device 100. Therefore, the electronic device 102 can prevent the underfill 50 from adhering to the protective electronic component 30 more effectively than the electronic device 100.

[0058] Furthermore, in the electronic device 102, the adsorbed electronic components 41 to 44 are arranged in parallel and perpendicular directions to the target electronic component 20. Therefore, the electronic device 102 can prevent the underfill 50 from adhering to the protective electronic component 30, regardless of the amount or direction in which the underfill 50 spreads.

[0059] (Variation 3) As shown in FIG. 5, electronic device 103 of modified example 3 includes a guide portion 70a. Electronic device 103 differs from electronic device 101 in the shape of guide portion 70a. Guide portion 70a has a third portion 73 in addition to a first portion 71 and a second portion 72. First portion 71 and second portion 72 are connected via third portion 73. Electronic device 103 can achieve the same effects as electronic device 101. Note that guide portion 70a can also be applied to modified examples 2 and 4.

[0060] (Variation 4) 6, the electronic device 104 of the fourth modification differs from the electronic device 100 in the configuration of the attracted electronic components 41 and 42. The attracted electronic components 41 and 42 are arranged perpendicular to the side wall 20a of the target electronic component 20. In other words, the attracted electronic components 41 and 42 are arranged side by side in the X direction. The electronic device 104 can achieve the same effects as the electronic device 100.

[0061] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and modifications within the scope of equivalents. In addition, although various combinations and forms are shown in the present disclosure, other combinations and forms including only one element, more, or less than one element are also within the scope and spirit of the present disclosure. [Explanation of symbols]

[0062] 10... wiring board, 11... insulating base material, 12... wiring, 13... pad, S1... one surface, S2... back surface, 20... target electronic component, 21... main body, 22... electrode, S11... mounting surface, 20a... side wall, 30... protected electronic component, 41 to 44... adsorbed electronic component, 50... underfill, 60... solder, 100 to 104... electronic device

Claims

1. A wiring board (10), a first electronic component (20) mounted on the wiring board; an underfill (50) provided in at least a gap between the wiring board and the first electronic component; a second electronic component (30) mounted on the wiring board and to be protected from adhesion of the underfill; a third electronic component (41 to 44) mounted on the wiring board and capable of adsorbing the underfill; An electronic device in which at least a portion of the third electronic component is disposed in a coating area around the first electronic component where the underfill spreads and wets the area.

2. The electronic device according to claim 1 , wherein a plurality of the third electronic components are mounted on the wiring board.

3. The electronic device according to claim 2, wherein the third electronic components are arranged parallel to a sidewall (20a) of the first electronic component.

4. 4. The electronic device according to claim 2, wherein the third electronic components are arranged perpendicular to the sidewalls (20a) of the first electronic components.

5. 4. The electronic device according to claim 1, wherein the third electronic component is in contact with the underfill.

6. A guide portion (70) is provided on the wiring board, The electronic device according to claim 1 , wherein at least a part of the guide portion is disposed in the application area.

7. The electronic device according to claim 6 , wherein the induction portion is disposed between the first electronic component and the second electronic component.

8. The electronic device according to claim 6 , wherein the induction portion is a conductive wiring pattern.

9. 7. The electronic device according to claim 6, wherein the induction portion has a first portion (71) and a second portion (72) facing each of two side walls (20a, 20b) connected via a corner of the first electronic component.

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