Electronic device, base substrate, and manufacturing method

Abstract

To provide an electronic device with assured connection reliability.SOLUTION: An electronic device 100 includes a BGA component 20 mounted on a motherboard 10a. The BGA component 20 has a solder ball. The motherboard 10 includes a first land 13a connected to the solder ball on the mounting surface SF11 side on which the BGA component 20 is mounted. The motherboard 10 also includes a protrusion 14a provided around the first land 13a on the mounting surface SF11 for preventing the BGA component 20 from shifting out of position.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to an electronic device, a base substrate, and a manufacturing method. [Background technology]

[0002] Patent Document 1 discloses an electronic device in which a surface-mount package on which external connection bumps are formed is mounted on a motherboard. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 8-335647 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in electronic devices, the surface mount package may become misaligned with respect to the motherboard, which may result in a loss of connection reliability between the electrodes of the motherboard and the external connection bumps of the surface mount package.

[0005] One disclosed object is to provide an electronic device with ensured connection reliability. Another disclosed object is to provide a base substrate capable of positioning mounted components. Another disclosed object is to provide a manufacturing method capable of manufacturing an electronic device with ensured connection reliability. [Means for solving the problem]

[0006] The electronic device disclosed herein comprises: An electronic device in which a second circuit component (20) is mounted on a first circuit component (10a, 10b), The second circuit component includes a solder ball (32); The first circuit component is characterized by having electrode portions (13a, 31a) to which solder balls are connected on the mounting surface (SF11) on which the second circuit component is mounted, and protrusion portions (14a, 14b) provided around the electrode portions for preventing the second circuit component from shifting in position.

[0007] Since the electronic device includes the protrusion, the second circuit component can be positioned relative to the first circuit component, thereby ensuring connection reliability between the solder balls and the electrodes.

[0008] The base substrate disclosed herein comprises: A base substrate configured so that a mounting component (20) can be mounted via a solder ball (32), Electrode portions (13a, 31a) to which solder balls are connected are provided on a mounting surface (SF11) on which components are mounted; The solder joint is characterized by having protrusions (14a, 14b) for preventing misalignment of mounted components, which are provided around the electrode portion on the mounting surface side.

[0009] Since the base substrate has the protrusions, the mounted components can be positioned relative to the base substrate.

[0010] The manufacturing method disclosed herein comprises: A method for manufacturing an electronic device in which a second circuit component (20) is mounted on a mounting surface (SF11) of a first circuit component (10a, 10b), comprising the steps of: A preparation step (S10, S11) of preparing a second circuit component having solder balls (32); a protrusion forming step (S23) of forming protrusions (14a, 14b) for suppressing misalignment of the second circuit component around electrode portions (13a, 31a) to which solder balls of the first circuit component are connected on the mounting surface side; a placement step (S24) of placing a second circuit component on the first circuit component after the protrusion forming step; The method further comprises a reflow step (S25) of transporting the structure in which the second circuit component is disposed on the first circuit component to a reflow furnace and soldering the solder balls and the electrodes.

[0011] In the manufacturing method, after the protrusion forming step, the structure in which the second circuit component is disposed on the first circuit component is transported to a reflow furnace for soldering. Therefore, the manufacturing method can suppress misalignment of the second circuit component relative to the first circuit component during transportation. Therefore, the manufacturing method can manufacture an electronic device in which the second circuit component is positioned relative to the first circuit component. In addition, the manufacturing method can manufacture an electronic device in which connection reliability between the solder balls and the electrodes is ensured.

[0012] The aspects disclosed in this specification adopt different technical means to achieve their respective objectives. The claims and the parenthetical symbols described in this section are illustrative of the corresponding relationship with the embodiments described below, and are not intended to limit the technical scope. The objectives, features, and effects disclosed in this specification will become clearer by referring to the following detailed description and the attached drawings. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a plan view showing a schematic configuration of an electronic device. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Diagram 3] FIG. 2 is a plan view showing a schematic configuration of a mother substrate. [Figure 4] FIG. 4 is an enlarged view of a portion IV in FIG. [Diagram 5] 1A to 1C are cross-sectional views illustrating steps in the preparation process of a BGA component. [Figure 6] 1A to 1C are cross-sectional views illustrating steps in a manufacturing method for an electronic device. [Figure 7] 1 is an enlarged cross-sectional view showing a BGA component mounting process. [Figure 8] 13 is a cross-sectional view showing a case where a BGA component is misaligned in a configuration having a protrusion. [Figure 9] 13 is a cross-sectional view showing a case where a BGA component is misaligned in a configuration that does not have a protrusion. [Figure 10] FIG. 11 is a plan view showing a schematic configuration of a motherboard according to a first modified example. [Figure 11] FIG. 11 is an enlarged view of a portion XI in FIG. [Figure 12] FIG. 11 is a plan view showing a schematic configuration of an electronic device according to a second modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] In the following, several embodiments for carrying out the present disclosure will be described with reference to the drawings. In each embodiment, the same reference numerals may be used to designate parts corresponding to matters described in the preceding embodiment, and duplicated descriptions may be omitted. In each embodiment, when only a part of the configuration is described, other parts of the configuration may be applied by referring to the other embodiment described earlier. In the following, the three mutually orthogonal directions are referred to as the X direction, the Y direction, and the Z direction.

[0015] (Embodiment) <Configuration of electronic device> An electronic device 100 will be described with reference to Figs. 1 to 9. As shown in Figs. 1, 2, etc., the electronic device 100 includes a motherboard 10a, a BGA component 20, etc. As shown in Fig. 6, an electronic component 40 is mounted on the motherboard 10a in addition to the BGA component 20. In the electronic device 100, the BGA component 20 and the electronic component 40 are stacked on the motherboard 10a in the Z direction. BGA is an abbreviation for Ball Grid Array.

[0016] In the electronic device 100, a circuit is formed by electrically connecting a motherboard 10a, a BGA component 20, and an electronic component 40. The electronic device 100 can be applied to a control device, etc. In this manner, it can be said that the electronic device 100 includes the motherboard 10a, the BGA component 20, and the electronic component 40 as circuit components that form the circuit. In this embodiment, the motherboard 10a corresponds to the first circuit component and the base substrate, the BGA component 20 corresponds to the second circuit component and the mounting component, and the electronic component 40 corresponds to the peripheral circuit component.

[0017] 6 and other figures, electronic component 40 is a circuit component smaller than BGA component 20 and motherboard 10a. BGA component 20 is a circuit component smaller than motherboard 10a. Note that "small" here refers to a small size at least when viewed from the Z direction.

[0018] <Motherboard configuration> The motherboard 10a will be described with reference to Figures 1, 2, 3, 6, etc. The motherboard 10a includes an electrically insulating base material 11 and a conductive wiring portion provided on the base material 11. The base material 11 is a substrate whose main component is, for example, resin. Therefore, the base material 11 can also be called a resin substrate. The motherboard 10a also includes a mounting surface SF11 on which the BGA component 20 and the like are mounted, and a surface SF12 opposite the mounting surface SF11. In Figure 3, the outline of the BGA component 20 is indicated by a dashed line.

[0019] The motherboard 10a has a protective film 12 provided on the mounting surface SF11. The protective film 12 is made of an electrically insulating resin or the like. The protective film 12 covers a part of the base material 11 and a part of the wiring portion for the purpose of protecting against adhesion of dust and damage. The protective film 12 is made of, for example, an epoxy resin or the like as a main component.

[0020] The part of the base material 11 is the surface on the mounting surface SF11 side, and is a portion on which the wiring portion is not provided. The part of the wiring portion is a portion of the wiring layer in the wiring portion. The part of the wiring layer is a portion on the mounting surface SF11 side of the wiring layer, and is a portion excluding lands 13a, 13b, which will be described later. In other words, the protective film 12 covers the wiring layer provided on the mounting surface SF11 side so that the lands 13a, 13b are exposed. The symbol SF13 in FIG. 2 etc. indicates the surface of the protective film 12.

[0021] The wiring section includes wiring layers stacked via the substrate 11 and an interlayer connection section that electrically connects the wiring layers of different layers. The wiring layers are provided inside the substrate 11 and on the surface of the substrate 11. The wiring layers include lands 13a and 13b that are part of the area exposed on the mounting surface SF11 side.

[0022] 6, the motherboard 10a includes a plurality of first lands 13a and a plurality of second lands 13b. The lands 13a and 13b function as electrodes for external connection. The term "for external connection" means that the lands are used for connection to a BGA component 20, an electronic component 40, or the like provided outside the motherboard 10a.

[0023] 2, the first land 13a is connected to the BGA component 20. More specifically, the first land 13a is connected to the BGA component 20 via a solder connection portion 30. The solder connection portion 30 is formed by joining a solder ball 32 and a receiving solder 31a. Therefore, it can be said that the solder ball 32 of the BGA component 20 is connected to the first land 13a. The first land 13a can also be said to be a land for the BGA component 20.

[0024] The first land 13a corresponds to at least a part of the electrode portion. The first land 13a corresponds to at least a part of the electrode portion. The first land 13a corresponds to at least a part of the electrode portion. The first land 13a will be described in detail later.

[0025] The multiple first lands 13a are provided corresponding to the multiple solder balls 32 of the BGA component 20. Therefore, in Fig. 1, the first lands 13a are provided at locations where the solder connection portions 30 are illustrated.

[0026] In this way, the mother substrate 10a has a plurality of first lands 13a arranged in a plurality of rings. It can also be said that the mother substrate 10a has a plurality of ring portions in which the plurality of first lands 13a are arranged in a ring shape. In this embodiment, as an example, a configuration in which the plurality of first lands 13a are arranged in five rows and five columns is adopted. However, the number of first lands 13a is not limited to this.

[0027] The second land 13b is provided around the first land 13a. The electronic component 40 is connected to the second land 13b. In other words, the electrode of the electronic component 40 is connected to the second land 13b. As with the first land 13a, the second land 13b has an incoming solder 31b formed thereon. The second land 13b is electrically connected to the electrode of the electronic component 40 via the incoming solder 31b. The second land 13b corresponds to at least a part of the peripheral electrode portion. The incoming solder 31b can also be considered as a part of the peripheral electrode portion. The incoming solder 31b will be explained in more detail later.

[0028] Furthermore, as shown in FIGS. 1 to 3, the motherboard 10a includes protrusions 14a provided around the first lands 13a for preventing misalignment of the BGA component 20. The protrusions 14a are provided on the mounting surface SF11 side, similar to the first lands 13a. In this embodiment, as an example, the protrusions 14a provided on the protective film 12 are used. However, the present disclosure is not limited to this, and protrusions 14a provided on the mounting surface SF11 may also be used. The protrusions 14a will be described in detail later.

[0029] In this embodiment, a multilayer substrate with laminated wiring layers is adopted as the mother substrate 10a. However, the present disclosure is not limited to this. The mother substrate 10a can also be referred to as a wiring substrate or a main substrate. Further, a multi-chip module can also be adopted as the mother substrate 10a.

[0030] <Configuration of BGA Component> The BGA component 20 will be described with reference to FIGS. 1, 2, 5, etc. As shown in FIGS. 2, 5, etc., the BGA component 20 includes an electrically insulating base material 21, a bare chip-shaped semiconductor chip 22, an electrically insulating encapsulating resin 23, and solder balls 32. Further, the BGA component 20 includes a facing surface SF21 with respect to the mother substrate 10a and a surface SF22 opposite to the facing surface SF21. Note that in FIG. 5, the semiconductor chip 22 is omitted.

[0031] The base material 21 is, for example, a substrate mainly composed of resin. Therefore, the base material 21 can also be referred to as a resin substrate. The semiconductor chip 22 is mounted on the base material 21 and encapsulated with the encapsulating resin 23.

[0032] The solder balls 32 are provided on the facing surface SF21 side. The solder balls 32 are electrically connected to the semiconductor chip 22. For example, the solder balls 32 are electrically connected to the semiconductor chip 22 via a wiring pattern provided on the base material 21 or the like. The solder balls 32 have a shape in which a part of the spherical shape is crushed by the base material 21.

[0033] Note that a protective film may be provided at a portion of the BGA component 20 that faces the mother substrate 10a. In this case, the surface of the protective film becomes the facing surface SF21. Further, the BGA component 20 may be provided with a facing surface land that is a part of the wiring pattern provided on the base material 21 and is exposed on the facing surface SF21 side. In this case, the solder balls 32 are connected to the facing surface land. The facing surface land can be regarded as an electrode of the BGA component 20.

[0034] The solder balls 32 are provided to electrically connect the semiconductor chip 22 to the motherboard 10a (first lands 13a). That is, the semiconductor chip 22 is electrically connected to the motherboard 10a by connecting the solder balls 32 to the first lands 13a. The BGA component 20 has the solder balls 32 provided at multiple locations on the facing surface SF21.

[0035] A discrete component, a module component having multiple semiconductor chips that constitute a system, or the like can be used as the BGA component 20. The module component can also be called a system on chip (SoC) or a multi-chip module.

[0036] 2, the present embodiment employs, as an example, a BGA component 20 on which an electronic component 24 is mounted. The BGA component 20 has the electronic component 24 mounted on a facing surface SF21 side. It can also be said that the electronic component 24 is disposed in an opposing region between the motherboard 10a and the BGA component 20. Hereinafter, the opposing region between the motherboard 10a and the BGA component 20 will also be simply referred to as the opposing region.

[0037] The electronic component 24 is a circuit component disposed in the facing region. The electronic component 24 corresponds to a facing circuit component. The facing region is a region where the mounting surface SF11 and the facing surface SF21 face each other in the Z direction.

[0038] The electronic component 24 is electrically connected to the semiconductor chip 22. Discrete components can be used as the electronic component 24. Discrete components are electronic components having a single function, such as MOSFETs, IGBTs, diodes, and resistor elements.

[0039] The electronic device 100 does not necessarily have to include the electronic component 24. The electronic device 100 may also be provided on a motherboard 10a.

[0040] <Electronic components> As shown in FIG. 6, the electronic component 40 is a circuit component provided around the BGA component 20. The electronic component 40 has electrodes. As described above, the electronic component 40 is electrically connected to the second land 13b. A discrete component can be used as the electronic component 40. The electronic component 40 corresponds to a peripheral circuit component. Note that the electronic device 100 can also be configured without the electronic component 40.

[0041] <Protrusion> 2, 3, and 4, the protrusion 14a will be described. The protrusion 14a is provided on the front surface SF13 of the protective film 12 in contact with the protective film 12. The protrusion 14a is a portion that protrudes in the Z direction from the surrounding area of ​​the protrusion 14a. In other words, the protrusion 14a is a portion that protrudes from the front surface SF13 toward the BGA component 20. The protrusion 14a may be provided on the mounting surface SF11.

[0042] The protrusions 14a are members for preventing the BGA component 20 from being misaligned with respect to the motherboard 10a during manufacturing. In other words, the protrusions 14a prevent the solder balls 32 from being misaligned with respect to the first lands 13a. Misalignment of the BGA component 20 can also be considered as movement of the BGA component 20. In this embodiment, as an example, an example in which the protrusions 14a are provided in two places is adopted.

[0043] The protrusions 14a may be made of, for example, a material mainly made of resin. In this case, the motherboard 10a has a structure in which the resin of the protective film 12 and the resin of the protrusions 14a are laminated. In this embodiment, an example in which the protective film 12 and the protrusions 14a are separate bodies is used. However, the protective film 12 and the protrusions 14a may be provided as an integral body.

[0044] Furthermore, the protrusions 14a are preferably made of a material that repels solder materials such as the solder balls 32. In other words, the protrusions 14a are preferably made of a material that is not wetted by the solder material. This makes it possible to prevent the solder balls 32 and the protrusions 14a from being connected to each other even if the BGA component 20 is misaligned during manufacturing.

[0045] Moreover, it is preferable that the protrusions 14a are made of a material that does not melt at the temperature during reflow soldering. This prevents the solder balls 32 from being connected to the protrusions 14a even if the BGA component 20 is misaligned during soldering. The temperature during reflow soldering corresponds to the temperature in a reflow furnace.

[0046] The protrusions 14a are provided in the opposing region on the mounting surface SF11 side. That is, the protrusions 14a are provided between the substrate 11 and the BGA component 20. This allows the distance between the protrusions 14a and the solder balls 32 to be closer than in a configuration in which the protrusions 14a are provided outside the opposing region. Therefore, even if the BGA component 20 is misaligned, the misalignment can be minimized.

[0047] Furthermore, the motherboard 10 can improve the degree of freedom of arrangement outside the facing region compared to a configuration in which a suppressing member such as the protrusion 14a that suppresses misalignment outside the facing region is provided. In other words, the motherboard 10 can suppress a reduction in the arrangement area of ​​the circuit components outside the facing region. Therefore, the motherboard 10 can be provided with the protrusion 14a without increasing the size of the motherboard 10.

[0048] 3 and 4, the protrusion 14a includes a first protrusion 141 and a second protrusion 142. The first protrusion 141 and the second protrusion 142 are provided so as to intersect at right angles. It can be said that the protrusion 14a includes the first protrusion 141 extending in a first direction relative to the base, and the second protrusion 142 extending in a second direction relative to the base. The first direction and the second direction are perpendicular to each other on the XY plane.

[0049] The protrusion 14a can be said to be L-shaped in plan view. Plan view is a drawing when the XY plane is seen from the Z direction. The first protrusion 141 corresponds to a first portion. The second protrusion 142 corresponds to a second portion.

[0050] 4, the first protrusion 141 has a short side SF31 and a long side SF33 as sides along the X direction. The second protrusion 142 has a short side SF32 and a long side SF34 as sides along the Y direction. The angle between the short side SF31 and the short side SF32 is 90 degrees. The angle between the long side SF33 and the long side SF34 is 90 degrees. The directions along which the sides SF31 to SF34 follow differ depending on the arrangement.

[0051] The protrusion 14a is provided such that the first protrusion 141 extends along the X direction and the second protrusion 142 extends along the Y direction. Thus, the first protrusion 141 is a portion that extends along the X direction. The second protrusion 142 is a portion that extends along the Y direction.

[0052] The first protrusion 141 is provided adjacent to the nearest first land 13a in the Y direction. The second protrusion 142 is provided adjacent to the nearest first land 13a in the X direction. In addition, the protrusion 14a is disposed such that the short side portions SF31, SF32 face the first land 13a.

[0053] The nearest first land 13a can also be considered as a target land for the protrusion 14a. In the example of Fig. 4, the first land 13 indicated by reference numeral 13a is the target land. The target land corresponds to a target electrode.

[0054] Moreover, the protrusions 14a are provided in four directions along the mounting surface SF11 around at least two first lands 13a. The four directions are the positive and negative X directions and the positive and negative Y directions. The X and Y directions are two orthogonal directions along the mounting surface SF11. The positive and negative X directions are two directions that start from the center of the mounting surface SF11 in the facing region. Similarly, the positive and negative Y directions are two directions that start from the center.

[0055] In this embodiment, an example is adopted in which the first protrusion 141 and the second protrusion 142 of the two protrusions 14a are provided in four directions. The first protrusion 141 of one protrusion 14a is a portion provided in the positive direction of the X direction. The first protrusion 141 of the other protrusion 14a is a portion provided in the negative direction of the X direction. Moreover, the second protrusion 142 of one protrusion 14a is a portion provided in the positive direction of the Y direction. The second protrusion 142 of the other protrusion 14a is a portion provided in the negative direction of the Y direction.

[0056] At least two first lands 13a are disposed between an imaginary straight line that runs along the two first protrusions 141. Therefore, it can be said that the two first protrusions 141 are provided so as to sandwich at least two first lands 13a in the Y direction. The imaginary straight line in this case runs along the X direction.

[0057] At least two first lands 13a are disposed between an imaginary straight line that runs along the two second protrusions 142. Therefore, it can be said that the two second protrusions 142 are provided so as to sandwich at least two first lands 13a in the X direction. The imaginary straight line in this case runs along the Y direction.

[0058] The protrusions 14a are provided to prevent movement of the BGA component 20 in the orthogonal X and Y directions. The two first protrusions 141 are portions that suppress misalignment of the BGA component 20 in the Y direction. On the other hand, the two second protrusions 142 are portions that suppress misalignment of the BGA component 20 in the X direction. Note that the protrusions 14a may be capable of suppressing misalignment in at least one of the X and Y directions.

[0059] 3, the protrusion 14a is provided on the periphery of the first land 13a surrounded by the outermost first land 13a. It can also be said that the protrusion 14a is provided at a position surrounded by the outermost first land 13a.

[0060] This makes it easier for the electronic device 100 to accommodate the protrusion 14a within the facing region. Also, the electronic device 100 can provide the protrusion 14a by effectively utilizing the dead space in the facing region. Furthermore, the electronic device 100 can eliminate component layout restrictions due to the adhesion of resin material to the periphery when forming the protrusion 14a and the resin overflowing. However, the present disclosure is not limited thereto. The protrusion 14a may be provided around the outermost first land 13a.

[0061] As shown in Fig. 4, the protrusion 14a is preferably provided at a location where the distance D1 between the protrusion 14a and the target land 13a is equal to or less than half the diameter B1 of the target land 13a. In other words, the protrusion 14a is preferably provided so as to satisfy the relationship 0 < D1 < B1 / 2. The distance D1 is, for example, the shortest distance between a virtual line along the short side portion SF31 in the X direction and a virtual line passing through an end of the first land 13a, which is the target land, and running along the X direction. The distance D1 is, for example, the shortest distance between a virtual line along the short side portion SF32 in the Y direction and a virtual line passing through an end of the first land 13a, which is the target land, and running along the Y direction.

[0062] Note that the distance D2 only needs to be 0 or more. The distance D2 is, for example, the shortest distance between a virtual straight line along the long side portion SF33 in the X direction and a virtual straight line along the X direction passing through the end of the first land 13a. Also, the distance D2 is, for example, the shortest distance between a virtual straight line along the long side portion SF34 in the Y direction and a virtual straight line along the Y direction passing through the end of the first land 13a.

[0063] For example, when the displacement exceeds half of the diameter B1, the solder ball 32 may be connected to the first land 13a adjacent to the corresponding first land 13a. However, by satisfying the above relationship, the electronic device 100 can suppress the displacement of the BGA component 20 within the range where the corresponding solder ball 32 can be connected to the first land 13a.

[0064] Note that the distance D1 can also be said to be the distance between the protrusion 14a and the closest point of the target land 13a. The diameter B1 of the target land 13a is equal to the diameter of the incoming solder 31a. The corresponding solder ball 32 and the first land 13a are the solder ball 32 and the first land 13a that should be originally connected.

[0065] Also, as shown in FIG. 2, it is preferable that the height of the protrusion 14a is higher than the height Z1 of the electronic component 24 and smaller than the distance Z3 between the mother board 10a and the BGA component 20. That is, it is preferable that the protrusion 14a is provided so as to satisfy the relationship of Z1 < Z2 < Z3. Thereby, the electronic device 100 can suppress the electronic component 24 from contacting the mother board 10a. However, the present disclosure is not limited to this, and Z2 ≦ Z3 is sufficient.

[0066] <Manufacturing method of electronic device> Here, with reference to FIGS. 5 and 6, the manufacturing method of the electronic device 100 will be described. In the present embodiment, as an example, a manufacturing method including a flux transfer process is adopted. However, the electronic device 100 can also be manufactured by other manufacturing methods. Hereinafter, the steps can also be referred to as steps.

[0067] 5, a preparation process (preparation step) for preparing a BGA component 20 having solder balls 32 will be described. First, a chip component preparation process S10 for preparing the BGA component 20 is performed. In this process, a chip component is prepared in which solder bumps 32a, which are part of the solder balls 32, are formed on a substrate 21, a semiconductor chip 22, and a sealing resin 23. The solder bumps 32a have the same shape as the solder balls 32.

[0068] Next, a flux transfer step S11 is performed. In this step, the flux material 210 is placed in the container 200, and the container 200 and the chip component are brought relatively close to each other. Then, the solder bumps 32a are pressed against the flux material 210 placed in the container 200. As a result, the flux material 210 is transferred to the surface of the solder bumps 32a, and the flux 32b is formed. Furthermore, the flux transfer step S11 forms solder balls 32 including the solder bumps 32a and the flux 32b.

[0069] In this embodiment, the solder ball 32 includes the solder bump 32a and the flux 32b. However, the solder ball 32 may include only the solder bump 32a. That is, the solder ball 32 may be the solder bump 32a.

[0070] A method for manufacturing the mother substrate 10a and the electronic device 100 will be described with reference to Fig. 6. Note that the protective film 12 and the electronic components 24 are omitted in Fig. 6 to avoid complicating the drawing. Also, the protrusions 14a are illustrated in a simplified form in Fig. 6.

[0071] In the solder printing process S20, the receiving solders 31a, 31b are printed on the lands 13a, 13b formed on the base material 11. Through this process, the receiving solder 31a is formed on the first land 13a. Also, the receiving solder 31b is formed on the second land 13b. The first land 13a and the receiving solder 31a are electrode portions to which the solder balls 32 are connected. The second land 13b and the receiving solder 31b are peripheral electrode portions to which the electrodes of the electronic component 40 are connected.

[0072] In the component mounting process S21, an electronic component 40 is mounted on the motherboard 10a. In this process, the electrodes of the electronic component 40 are aligned with the receiving solder 31b formed on the second land 13b. Then, the electronic component 40 is mounted on the motherboard 10a so that the electrodes of the electronic component 40 and the receiving solder 31b are in contact with each other.

[0073] In this case, mounting means placing the electronic component 40 on the mother board 10a. Mounting can also be rephrased as placing or arranging.

[0074] In the first reflow process S22, the motherboard 10a on which the electronic components 40 are mounted is transported to a reflow furnace. Then, in the reflow furnace, the electrodes of the electronic components 40 and the second lands 13b are soldered with the receiving solder 31b. In the first reflow process S22, the BGA components 20 are not placed on the receiving solder 31a. Therefore, the receiving solder 31a melts in the reflow furnace and becomes hemispherical.

[0075] This step is performed before the BGA component mounting step S24, which will be described later. The first reflow step S22 corresponds to a pre-reflow step.

[0076] In the protrusion forming process S23, the protrusion 14 is formed around the first land 13a on the mounting surface SF11 side. More specifically, the protrusion 14a is formed around the target land 13a. The protrusion 14a is formed on the protective film 12 by coating or the like.

[0077] The protrusion forming process S23 may be performed between the solder printing process S20 and the component mounting process S21, or between the component mounting process S21 and the first reflow process S22. The protrusion forming process S23 corresponds to a protrusion forming step.

[0078] In the BGA component mounting process S24, after the protrusion forming process S23, the BGA component 20 is mounted on the motherboard 10a. In this process, the solder balls 32 are aligned with the receiving solders 31a formed on the first lands 13a. Then, the BGA component 20 is mounted on the motherboard 10a so that the solder balls 32 and the receiving solders 31a are in contact with each other. As described above, mounting here means placing the BGA component 20 on the motherboard 10a. The BGA component mounting process S24 corresponds to a placement step.

[0079] 7, the structure in which the BGA component 20 is arranged on the motherboard 10a has the solder balls 32 placed on the pre-solder 31a. In the second reflow process S25, which will be described later, the structure is transported to a reflow furnace. During this process, external forces such as vibrations are applied to the structure.

[0080] 9, the BGA component 20 may be displaced from its aligned state by an external force. That is, the solder balls 32 slide off the welcoming solder 31a, causing the BGA component 20 to move. When the BGA component 20 moves in this manner, the positions of the solder balls 32 and the welcoming solder 31a (first lands 13a) become misaligned.

[0081] Furthermore, there is a risk that the solder balls 32 and the receiving solder 31a may not be connected to each other depending on the amount of movement of the BGA component 20. Also, there is a risk that the structure may end up in a state where the solder balls 32 and the receiving solder 31a that are not originally meant to be connected come into contact with each other.

[0082] If the second reflow process S25 is performed in this state, there is a risk of poor connection in the solder connection portion 30. Therefore, this state can be said to be a defective state. Therefore, Fig. 9 can be said to show a structure in a defective state. On the other hand, the state in which the solder ball 32 and the receiving solder 31a that should be connected are in contact can be said to be a good state.

[0083] Therefore, in the present manufacturing method, the protrusions 14a are formed as described above. As shown in Fig. 8, by forming the protrusions 14a, the movement of the BGA component 20 is restricted. In other words, even if the BGA component 20 is moved by an external force, the solder balls 32 stay at a position where they contact the protrusions 14a. Therefore, in the present manufacturing method, even if the structure is transported to a reflow furnace, it is possible to prevent the structure from becoming defective. Note that Fig. 8 shows a structure in a good condition.

[0084] In the second reflow process S25, the structure in which the BGA component 20 is arranged on the motherboard 10a is transported to a reflow furnace. Then, in the reflow furnace, the electrodes of the BGA component 20 and the first lands 13a are soldered with the solder balls 32 and the receiving solder 31a. That is, the solder balls 32 and the receiving solder 31a are joined to form the solder connection parts 30. It can also be said that the electrodes of the BGA component 20 and the first lands 13a are electrically connected by the solder connection parts 30.

[0085] In particular, in this embodiment, the second reflow process S25 is performed after the protrusion forming process S23. Therefore, in the second reflow process S25, soldering can be performed on a structure in good condition. Note that the second reflow process S25 corresponds to a reflow step.

[0086] The present manufacturing method including these steps can manufacture the electronic device 100. Note that the present disclosure does not require the use of the receiving solders 31a and 31b. In this case, the first land 13a corresponds to the electrode portion, and the second land 13b corresponds to the peripheral electrode portion.

[0087] <Effects> As described above, the electronic device 100 includes the protrusions 14a. Therefore, the electronic device 100 can be configured such that the BGA component 20 is positioned relative to the motherboard 10a. Therefore, the electronic device 100 can ensure the connection reliability between the solder balls 32 and the first lands 13a. In other words, the electronic device 100 suppresses open defects and short defects in the solder connection portions 30.

[0088] Furthermore, the motherboard 10a includes protrusions 14a, which allow the BGA component 20 to be positioned relative to the motherboard 10a.

[0089] Furthermore, in the manufacturing method, after the protrusion forming step S23, the structure is transported to a reflow furnace and soldered. Therefore, the manufacturing method can suppress misalignment of the BGA component 20 with respect to the motherboard 10a during transportation. Therefore, the manufacturing method can manufacture the electronic device 100 in which the BGA component 20 is positioned with respect to the motherboard 10a. Furthermore, the manufacturing method can manufacture the electronic device 100 in which the connection reliability between the solder balls 32 and the first lands 13a is ensured.

[0090] The protrusions 14a are provided in four directions along the mounting surface SF11 around at least two first lands 13a. This allows the electronic device 100 to suppress rotational misalignment of the BGA component 20.

[0091] The above describes the preferred embodiment of the present disclosure. However, the present disclosure is not limited to the above embodiment, and various modifications are possible within the scope of the present disclosure. Below, as other embodiments of the present disclosure, Modifications 1 and 2 are described. The above embodiment and Modifications 1 and 2 can be implemented alone, but can also be implemented in appropriate combination. The present disclosure is not limited to the combinations shown in the embodiments, and can be implemented in various combinations.

[0092] (Variation 1) The electronic device 100 of the first modification will be described with reference to Figures 10 and 11. The electronic device 100 of the first modification differs from the above embodiment in the configuration of the motherboard 10b. The motherboard 10b includes a protrusion 14b. The electronic device 100 of the first modification can be manufactured by the same manufacturing method as the above embodiment.

[0093] 10, the motherboard 10b includes a protrusion 14b that is cross-shaped in a plan view. The protrusion 14b can be said to have a shape in which two protrusions 14a are combined.

[0094] As shown in Fig. 11, the protrusion 14b includes a first protrusion 143, a second protrusion 144, a third protrusion 145, and a fourth protrusion 146. The first protrusion 143 is provided so as to be perpendicular to the second protrusion 144 and the fourth protrusion 146. The third protrusion 145 is provided so as to be perpendicular to the second protrusion 144 and the fourth protrusion 146. The first protrusion 143 and the third protrusion 145 are provided linearly. The second protrusion 144 and the fourth protrusion 146 are provided linearly.

[0095] Moreover, the first protrusion 143 and the third protrusion 145 are arranged along the X direction. Therefore, the second protrusion 144 and the fourth protrusion 146 are arranged along the Y direction. Therefore, the protrusions 14b are provided in four directions along the mounting surface SF11 around at least two first lands 13a.

[0096] The first protrusion 143 is a portion provided in the negative direction of the X direction. The third protrusion 145 is a portion provided in the positive direction of the X direction. The second protrusion 144 is a portion provided in the negative direction of the Y direction. The fourth protrusion 146 is a portion provided in the positive direction of the Y direction. In the example of FIG. 11, the first land 13 indicated by the reference symbol 13a is the target land.

[0097] 11, the first protrusion 143 has a side SF41 along the X direction and a side SF43 along the Y direction. The second protrusion 144 has a side SF42 along the Y direction and a side SF44 along the X direction. The third protrusion 145 has a side SF45 along the Y direction. The fourth protrusion 146 has a side SF46 along the X direction. The angle between the side SF41 and the side SF42 is 90 degrees.

[0098] The first protrusion 143 is provided adjacent to the nearest first land 13a in the Y direction. The second protrusion 144 is provided adjacent to the nearest first land 13a in the X direction. Moreover, the protrusion 14b is disposed such that the side portions SF41, SF42 face the first land 13a. In the example of FIG. 11, the first land 13 indicated by the reference symbol 13a is the target land.

[0099] Distance D1 is, for example, the shortest distance between a virtual line along side portion SF41 in the X direction and a virtual line passing through an end of first land 13a, which is the target land, and running along the X direction. Distance D1 is, for example, the shortest distance between a virtual line along side portion SF42 in the Y direction and a virtual line passing through an end of first land 13a, which is the target land, and running along the Y direction. The relationship between distance D1 and diameter B1 is the same as in the above embodiment. Distance D3 may be any distance as long as it is equal to or greater than B1 / 2.

[0100] As described above, the electronic device 100 of the first modification has only one protrusion 14b. The single protrusion 14b is provided so as to prevent the BGA component 20 from moving in two perpendicular directions along the mounting surface SF11. Therefore, the electronic device 100 of the first modification can reduce the number of components. The first modification can achieve the same effects as the above embodiment.

[0101] (Variation 2) An electronic device 100 according to the second modification will be described with reference to Fig. 12. As shown in Fig. 12, the electronic device 100 may include an underfill 50 and a dam portion 51 for preventing the underfill 50 from spreading.

[0102] The underfill 50 and the dam portion 51 are made of a liquid curable resin. An epoxy resin or the like can be used as the liquid curable resin for the underfill 50 and the dam portion 51. The underfill 50 and the dam portion 51 are provided on the protective film 12.

[0103] The underfill 50 seals the opposing area (gap) between the mother substrate 10a and the BGA component 20. A part of the underfill 50 is provided protruding outside the opposing area. The underfill 50 is formed after the second reflow process S25. The dam portion 51 is formed, for example, in the same process as the protrusion portion 14a.

[0104] The dam portion 51 prevents the overflowing underfill 50 from spreading more than necessary. In other words, the dam portion 51 is provided so that the underfill 50 is formed within a predetermined range. The dam portion 51 is provided so as to surround the BGA component 20 in the XY plane. Note that the electronic device 100 of the second modification does not necessarily need to be provided with the dam portion 51. It is preferable that the protrusion portion 14a is formed of the same material as at least one of the underfill 50 and the dam portion 51.

[0105] The electronic device 100 of the second modification may also use the protruding portion 14b. The underfill 50 and the dam portion 51 may be made of different materials. The electronic device 100 may also use the dam portion 51 as the protruding portion 14a.

[0106] Although the present disclosure has been described based on the embodiment, it is understood that the present disclosure is not limited to the embodiment or structure. The present disclosure also encompasses various modifications and modifications within the equivalent range. In addition, although various combinations and forms are shown in the present disclosure, other combinations and forms including only one element, more than one element, or less than one element are also within the scope and concept of the present disclosure. [Explanation of symbols]

[0107] 10a, 10b... mother board, 13a... first land, 14a... protrusion, 20... BGA component, 32... solder ball, 31a... solder ball, 100... electronic device

Claims

1. An electronic device in which a second circuit component (20) is mounted on a first circuit component (10a, 10b), The second circuit component comprises a solder ball (32); The first circuit component is an electronic device having an electrode portion (13a, 31a) to which the solder ball is connected on the mounting surface (SF11) side on which the second circuit component is mounted, and a protrusion portion (14a, 14b) provided around the electrode portion for suppressing misalignment of the second circuit component.

2. The electronic device according to claim 1 , wherein the protrusions are provided in four directions along the mounting surface around at least two of the electrodes.

3. The protrusion is a first portion that sandwiches at least two of the electrode portions in one of two orthogonal directions along the mounting surface; The electronic device according to claim 1 , further comprising: a second portion that sandwiches at least two of the electrode portions in the other of the two directions.

4. 3. The electronic device according to claim 1, wherein the protrusion is provided so as to prevent movement of the second circuit component in two perpendicular directions along the mounting surface.

5. the first circuit component has a plurality of the electrode portions arranged in a plurality of annular shapes, The electronic device according to claim 1 , wherein the protrusion is provided on a periphery of the electrode portion surrounded by the outermost electrode portion.

6. 3. The electronic device according to claim 1, wherein the protrusion is provided at a position where the distance to a target electrode, which is the electrode portion disposed closest to the protrusion, is equal to or less than half the diameter of the target electrode.

7. At least one of the first circuit component and the second circuit component includes an opposing circuit component (24) disposed in an opposing region between the first circuit component and the second circuit component, 3. The electronic device according to claim 1, wherein a height of the protrusion is greater than a height of the opposing circuit component and is smaller than a distance between the first circuit component and the second circuit component.

8. An underfill (50) is provided between the first circuit component and the second circuit component, The electronic device according to claim 1 , wherein the protrusion is made of the same material as the underfill.

9. A dam portion (51) for preventing the underfill from spreading is provided around the underfill, The electronic device according to claim 8 , wherein the protrusion is made of the same material as the dam.

10. A base substrate configured so that a mounting component (20) can be mounted via solder balls (32), Electrode portions (13a, 31a) to which the solder balls are connected are provided on a mounting surface (SF11) on which the mounting components are mounted; and protrusions (14a, 14b) for preventing the mounted components from shifting from their original position, the protrusions being provided around the electrode portions on the mounting surface side.

11. A method for manufacturing an electronic device in which a second circuit component (20) is mounted on a mounting surface (SF11) of a first circuit component (10a, 10b), comprising the steps of: a preparation step (S10, S11) of preparing the second circuit component having solder balls (32); a protrusion forming step (S23) of forming protrusions (14a, 14b) for suppressing misalignment of the second circuit component around electrode portions (13a, 31a) to which the solder balls of the first circuit component are connected on the mounting surface side; a placement step (S24) of placing the second circuit component on the first circuit component after the protrusion forming step; and a reflow step (S25) of transporting the structure in which the second circuit component is disposed on the first circuit component to a reflow furnace and soldering the solder balls and the electrode portions.

12. The first circuit component includes, in addition to the electrode portion, a peripheral electrode portion (13b, 31b) provided around the electrode portion, the electrode portion and the peripheral electrode portion each include solder on a surface thereof; the electronic device includes a peripheral circuit component (40) connected to the peripheral electrode portion around the second circuit component, The manufacturing method according to claim 11, further comprising a pre-reflow step (S22) of soldering the peripheral electrode portion and the peripheral circuit component in the reflow furnace before the placement step.

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