Method for manufacturing an electronic module and electronic module

Abstract

Provided is a method for manufacturing an electronic module capable of miniaturizing the electronic module, and an electronic module. The method for manufacturing an electronic module includes the following steps: a first step of applying solder paste (53) over a through-hole (31) of a printed board (30); a second step; and a third step of melting the solder paste (35) by reflow soldering. In the second step, a first electronic component (10) is arranged with a lead (12) of the first electronic component (10) inserted into the through-hole (31), and a second electronic component (20) is arranged so that a connection component for surface mounting of the second electronic component (20) is in contact with a pad (32) for connection of the printed board (30). The height of the connection component on the first electronic component (10) side is higher than the height of the solder paste (35). In the second step, at least a portion of the second electronic component (20) overlaps a portion of the solder paste (35) when viewed from above.

Description

Technical Field

[0001] This invention relates to a method for manufacturing an electronic module and the electronic module itself. Background Technology

[0002] Conventionally, soldering techniques have been used when mounting components on a printed circuit board. Among these soldering techniques, through-hole reflow soldering is known (e.g., Patent Document 1).

[0003] Patent Document 1 describes a method in which solder paste is applied to the through-holes of a printed circuit board, leads of an insertable mounting component are inserted into the through-holes of the printed circuit board, and the solder paste is heated by a heat source.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2014-36176

[0005] In existing soldering techniques that utilize through-hole reflow soldering, there is room for improvement in the miniaturization of electronic modules. For example, in the prior art, it is required to ensure the area of ​​solder paste application on the printed circuit board. In the prior art, it is sometimes difficult to miniaturize the printed circuit board in order to ensure the area of ​​solder paste application.

[0006] If the electronic module is miniaturized, the electronic device containing that electronic module can be miniaturized. Summary of the Invention

[0007] Therefore, the object of the present invention is to provide a method for manufacturing an electronic module and an electronic module that enables miniaturization of the electronic module.

[0008] The manufacturing method of the electronic module according to several embodiments of the present invention includes the following steps: a first step of applying solder paste over through-holes of a printed circuit board; a second step of arranging a first electronic component having leads and a second electronic component having surface mount connection members on the same side of the printed circuit board, inserting the leads into the through-holes to arrange the first electronic component, and arranging the second electronic component such that the connection members are in contact with the connection pads of the printed circuit board; and a third step of melting the solder paste by reflow soldering, wherein the height of the connection members located on the side of the first electronic component is higher than the height of the solder paste, and in the second step, at least a portion of the second electronic component overlaps with a portion of the solder paste when viewed from above. Since the height of the solder balls on the side of the first electronic component is higher than the height of the solder paste, insulation between the second electronic component and the solder paste can be ensured even when the second electronic component overlaps with the solder paste when viewed from above. By making the second electronic component overlap with the solder paste when viewed from above, the area of ​​the printed circuit board can be reduced. Because the area of ​​the printed circuit board is reduced, the finished electronic module can be miniaturized.

[0009] In one embodiment of the method for manufacturing an electronic module, the following steps may also be included: a fourth step, after performing the third step, where solder paste is applied to one of the two surfaces of the printed circuit board, on the side of the printed circuit board where the first electronic component is not disposed, and then a third electronic component is disposed opposite to the first electronic component; and a fifth step, where the solder paste applied in the fourth step is melted by reflow soldering. Because the third electronic component is disposed opposite to the first electronic component, the area of ​​the printed circuit board can be reduced compared to the case where the third electronic component is not disposed opposite to the first electronic component. Since the area of ​​the printed circuit board is reduced, the finished electronic module can be miniaturized.

[0010] In one embodiment of the electronic module manufacturing method, the first electronic component may be a connector for connecting to an external device, and the third electronic component may be a protective element for preventing surge current from entering the printed circuit board. The area where the through-hole is located is situated at the end of the printed circuit board. By placing the third electronic component, which serves as a protective element, at the end of the printed circuit board, surge current can be more effectively prevented from entering the interior of the printed circuit board in the finished electronic module.

[0011] In one embodiment of the electronic module manufacturing method, in the third step, the area where the via is located may be heated first, compared to the area where the solder pads are located. Heating the area where the via is located first, compared to the area where the solder pads are located, allows the solder paste to melt and flow into the via before the solder balls are heated. Since the solder paste flows into the via before the solder balls are heated, the insulation between the second electronic component and the solder paste can be more reliably ensured during the implementation of the third step.

[0012] In one embodiment of the electronic module manufacturing method, the connecting member located at least on the side of the first electronic component can also be a solder ball. The viscosity of the solder ball can be a high viscosity, higher than that of the solder paste. Because the solder ball has a high viscosity, in the implementation of the third step, the height of the solder ball can be maintained at a height higher than that of the solder paste. By maintaining the height of the solder ball higher than that of the solder paste in the implementation of the third step, insulation between the second electronic component and the solder paste can be ensured.

[0013] In one embodiment of the electronic module manufacturing method, the solder balls may also include a metal core or a resin core. In the third step, when the solder balls include a metal core or a resin core, the height of the solder balls can be more reliably maintained at a height higher than the solder paste height. With this structure, insulation between the second electronic component and the solder can be more reliably ensured in the third step.

[0014] In one embodiment of the electronic module manufacturing method, the second electronic component further has a base portion that is generally rectangular when viewed from above. Alternatively, two solder balls located at the two corners of the generally rectangular base portion may contain metal or resin cores. With this structure, insulation between the second electronic component and the solder paste can be more reliably ensured during the third process.

[0015] Several embodiments of the electronic module include a printed circuit board and a first electronic component and a second electronic component disposed on the same side of the printed circuit board. The distance between the first electronic component and the second electronic component is shorter than a predetermined length, and the second electronic component has solder balls with a height greater than or equal to a predetermined height. By making the distance between the first electronic component and the second electronic component shorter than a predetermined length, the electronic module can be miniaturized.

[0016] The effects of the invention

[0017] According to the present invention, a method for manufacturing an electronic module and an electronic module capable of miniaturizing the electronic module can be provided. Attached Figure Description

[0018] Figure 1 This is a flowchart illustrating a method for manufacturing an electronic module according to one embodiment of the present invention.

[0019] Figure 2 This is a front view of the first electronic component according to one embodiment of the present invention.

[0020] Figure 3 yes Figure 2 A top view of the first electronic component shown.

[0021] Figure 4 This is a front view of the second electronic component according to one embodiment of the present invention.

[0022] Figure 5 yes Figure 4 The bottom view of the second electronic component shown.

[0023] Figure 6 This is a top view of a printed circuit board according to one embodiment of the present invention.

[0024] Figure 7 This is a top view of the printed circuit board after the first process has been performed.

[0025] Figure 8 yes Figure 7 The side view of the printed circuit board shown.

[0026] Figure 9This is a top view of the printed circuit board after the second process has been performed.

[0027] Figure 10 yes Figure 9 The side view of the printed circuit board shown.

[0028] Figure 11 This is a side view of the printed circuit board after the third process has been performed.

[0029] Figure 12 This is a side view of the printed circuit board after the fourth process has been performed.

[0030] Figure 13 This is a side view of the printed circuit board after the fifth process has been performed.

[0031] Figure 14 This is a side view of the printed circuit board after the second process involved in the comparative example has been performed. Detailed Implementation

[0032] In this invention, "reflow soldering" includes, for example, placing a printed circuit board coated with solder paste in a reflow oven and heating the solder paste by means of infrared rays or hot air to melt it.

[0033] In this invention, "through-hole reflow soldering" may include: inserting the leads of an electronic component into a through-hole of a substrate coated with solder paste; and melting the solder paste by reflow soldering to mount the electronic component onto the substrate.

[0034] In this invention, "height" refers to the dimension in the thickness direction of the printed circuit board.

[0035] The embodiments of the present invention will now be described with reference to the accompanying drawings. In the structural elements shown in the following drawings, the same structural elements are labeled with the same reference numerals.

[0036] (Manufacturing method of electronic module)

[0037] Figure 1 This is a flowchart illustrating a method for manufacturing an electronic module according to one embodiment of the present invention. The method for manufacturing the electronic module includes the following steps: a first step S1, applying solder paste to a printed circuit board; a second step S2, disposing a first electronic component and a second electronic component on the printed circuit board; and a third step S3, heating the solder paste to melt it via reflow soldering. The method for manufacturing the electronic module may further include the following steps: a fourth step S4, disposing a third electronic component on the printed circuit board; and a fifth step S5, heating the solder paste applied in the fourth step to melt it via reflow soldering.

[0038] Below, refer to Figures 2 to 6The first electronic component, the second electronic component, and the printed circuit board used in the manufacturing method of the electronic module are described.

[0039] <First Electronic Component>

[0040] Figure 2 This is a front view of the first electronic component 10 according to one embodiment of the present invention. Figure 3 yes Figure 2 A top view of the first electronic component 10 shown.

[0041] Figure 2 as well as Figure 3 The first electronic component 10 shown may be a DIP (Dual In-line Package) component. The first electronic component 10 may be a component that can be mounted via through-hole reflow soldering.

[0042] The first electronic component 10 can be any type of electronic component. For example, the first electronic component 10 can be a connector for connecting to an external device.

[0043] like Figure 2 As shown, the first electronic component 10 has a main body 11 and at least one lead 12.

[0044] Various components are housed in the main body 11. The main body 11 may be approximately rectangular in shape. The main body 11 may include a frame. The frame of the main body 11 may be formed of any material, such as plastic or ceramic.

[0045] The lead wire 12 can be made of a metallic material. One end of the lead wire 12 is fixed to the bottom surface of the main body 11.

[0046] <Second Electronic Component>

[0047] Figure 4 This is a front view of the second electronic component 20 according to one embodiment of the present invention. Figure 5 yes Figure 4 The bottom view of the second electronic component 20 shown.

[0048] The second electronic component 20 can be any type of electronic component. For example... Figure 4 As shown, the second electronic component 20 includes a base portion 21, solder balls 22 serving as surface mount connection members, and a component 23. The surface mount connection member in the second electronic component 20 is not limited to solder balls 22. For example, the surface mount connection member in the second electronic component 20 could be a surface mount gasket or the like. Alternatively, the second electronic component 20 could have a main body portion housing various components, replacing the base portion 21 and the component 23.

[0049] The base portion 21 can be plate-shaped. For example... Figure 5 As shown, the base portion 21 can be roughly rectangular in shape when viewed from above. The base portion 21 can be a component corresponding to the type of the second electronic component. For example, the base portion 21 can be a printed circuit board.

[0050] like Figure 4 As shown, the solder ball 22 is located on one of the two surfaces included in the plate-shaped base portion 21. (As indicated...) Figure 5 As shown, when the base portion 21 is approximately rectangular in shape when viewed from above, the solder balls 22 can be located at the four corners of the base portion 21. However, the solder balls 22 may include at least solder balls 22A. Solder balls 22A are described later... Figure 10 As shown, after the second electronic component 20 is disposed on the printed circuit board 30 in the second process, it is located on the side of the first electronic component 10. Figure 5 In the middle, solder ball 22 faces... Figure 5 It is located on the right side of the paper.

[0051] The viscosity of solder ball 22 can be high. For example, the viscosity of solder ball 22 can be higher than that described later. Figure 10 The solder paste 35 shown has a higher viscosity.

[0052] The height h1 of solder ball 22A is higher than that described later. Figure 10 The height h2 of the solder paste 35 is shown. For example, as described below, when the height h2 of the solder paste is approximately 0.1 mm to 0.15 mm, the height h1 of the solder ball 22A can be higher than 0.15 mm. Figure 5 When viewed from above, the height of only two solder balls 22A located at the two corners of the generally rectangular base portion 21 may be higher than the height h2 of the solder paste 35 described later. Alternatively, the height of all solder balls 22A may be higher than the height h2 of the solder paste 35 described later, or the height of all solder balls 22 may be higher than the height h2 of the solder paste 35 described later.

[0053] Solder ball 22A may comprise a metal core such as copper or a resin core. When solder ball 22A has a metal core or resin core, it can be constructed by covering the spherical metal core or resin core with a solder layer. In such cases... Figure 5 When viewed from above, it is possible that only two solder balls 22A located at the two corners of the generally rectangular base portion 21 contain a metal core or a resin core. Alternatively, all solder balls 22A or all solder balls 22 may contain a metal core or a resin core.

[0054] Component 23 is disposed on the side of the plate-shaped base portion 21 that is not equipped with solder balls 22. Component 23 can be any type of electronic component.

[0055] <Printed substrate>

[0056] Figure 6 This is a top view of a printed circuit board 30 according to one embodiment of the present invention. The printed circuit board 30 is plate-shaped. The plate-shaped printed circuit board 30 includes a first surface 30A. As described later. Figure 8 As shown, the printed circuit board 30 includes a second surface 30B. The first surface 30A and the second surface 30B are opposite to each other.

[0057] The printed circuit board 30 has at least one through-hole 31 and at least one bonding pad 32. When the surface mount connection member of the second electronic component 20 is a surface mount gasket, the printed circuit board 30 may also have a nut in the center of the bonding pad 32 that engages with the gasket. For example, when performing steps 4 S4 and 5 S5, the printed circuit board 30 may have a coating on its second surface 30B that is then applied with the coating described later. Figure 12 The pads of solder paste 37 are shown.

[0058] A through-hole 31 penetrates the printed circuit board 30. The through-hole 31 extends from the first surface 30A to the second surface 30B. The printed circuit board 30 may have bonding pads around the through-hole 31 on the second surface 30B. (To be continued...) Figure 13 The solder 36 shown is able to bond with the pads around the through hole 31 on the second side 30B.

[0059] In the second step S2 described later, the leads 12 of the first electronic component 10 are inserted into the through-hole 31. The size and spacing of the through-hole 31 can be appropriately determined in accordance with the size and spacing of the leads 12 of the first electronic component 10. In the second step S2 described later, the first electronic component 10 is disposed in the area where the through-hole 31 is located. Hereinafter, the area where the first electronic component is disposed is also referred to as "first region 33". The position of the first region 33 on the printed circuit board 30 can be appropriately determined in accordance with the purpose of the first electronic component 10. For example, if the first electronic component 10 is a connector for connecting to an external device, the first region 33 is located in the area where the first electronic component 10 is located. Figure 6 The position shown in the top view can be such that at least a portion of the outer periphery of the first region 33 is adjacent to or connected to the outer periphery of the printed circuit board 30. In other words, after performing the second process S2 described later, in the following... Figure 10 When viewed from the side, the first region 33 can be located such that a portion of the first electronic component 10 is adjacent to or in contact with the end face of the printed circuit board 30.

[0060] In the second step S2 described later, solder balls 22 of the second electronic component 20 are arranged on pad 32. The size and spacing of the pad 32 can be appropriately determined in accordance with the size and spacing of the solder balls 22 of the second electronic component 20. In the second step S2 described later, the second electronic component 20 is arranged in the area where the pad 32 is located. Hereinafter, the area where the pad 32 is located is also referred to as "second area 34". The position of the second area 34 on the printed circuit board 30 can be appropriately determined in accordance with the purpose of the second electronic component 20.

[0061] <Step 1>

[0062] In the first process S1, as Figure 7 As shown, solder paste 35 is applied over the through-hole 31 on the first surface 30A of the printed circuit board 30. The solder paste 35 can be applied to a defined area on the first surface 30A, including the through-hole 31, over the solder resist. The solder paste 35 melts in the third step S3 described later, thereby flowing into the through-hole 31. The solder paste 35 flowing into the through-hole 31 in the third step S3 described later electrically connects the through-hole 31 to the lead 12 of the first electronic component 10.

[0063] In the first step S1, solder paste 35 can be applied to the vias 31 of the first region 33 via a metal mask. When solder paste 35 is applied via a metal mask, the shape of solder paste 35 can correspond to the shape of the opening of the metal mask. For example, when viewed from above, if the opening of the metal mask is approximately rectangular, the shape of solder paste 35 can also be approximately rectangular. When viewed from above, solder paste 35 can be applied such that the midpoint of the long side of solder paste 35 is located above the via 31. The solder paste 35 on each via 31 is separated from each other.

[0064] Figure 8 The height h2 of the solder paste 35 shown can be determined by the height of the opening of the metal mask. The height h2 of the solder paste 35 can be approximately the same as the height of the opening of the metal mask. The height of the opening of a typical metal mask is about 0.1 mm to 0.15 mm. When the solder paste 35 is applied through a typical metal mask, the height h2 of the solder paste 35 can be about 0.1 mm to 0.15 mm.

[0065] <Step 2>

[0066] In the second process S2, as Figure 9 as well as Figure 10 As shown, the first electronic component 10 and the second electronic component 20 are disposed on the same first surface 30A of the printed circuit board 30.

[0067] The first electronic component 10 is achieved by... Figure 2 The lead 12 shown is inserted into Figure 6 The through-hole 31 shown is configured accordingly. For example... Figure 9 As shown, when viewed from above, a portion of the solder paste 35 extends beyond the body portion 11 of the first electronic component 10 by only a length L.

[0068] The second electronic component 20 enables Figure 4 The solder ball 22 shown is Figure 7 The pads 32 shown are connected in a specific configuration.

[0069] In the second step 32, in Figure 9 As shown in the top view, at least a portion of the second electronic component 20 overlaps with a portion of the solder paste 35. For example, in the top view, a portion of the base portion 21 of the second electronic component 20 may overlap with a portion of the solder paste 35. Figure 10 As shown, the height h1 of the solder ball 22A on the first electronic component 10 side is higher than the height h2 of the solder paste 35. Because the height h1 of the solder ball 22A is higher than the height h2 of the solder paste 35, even if... Figure 9 As shown, when viewed from above, the second electronic component 20 overlaps with the solder paste 35, ensuring insulation between them. By making the second electronic component 20 overlap with the solder paste 35 when viewed from above, the area of ​​the printed circuit board 30 can be reduced. Because the area of ​​the printed circuit board 30 is reduced, the finished electronic module can be miniaturized.

[0070] <Step 3>

[0071] In step S3, reflow soldering is performed. In step S3, reflow soldering is used to... Figure 10 The first surface 30A of the printed circuit board 30 shown is heated.

[0072] In step S3, solder paste 35 is heated and melted by reflow soldering. The molten solder paste 35 flows into the through-hole 31. A portion of the solder paste 35 flowing into the through-hole 31 reaches the second surface 30B and adheres to the pads around the through-hole 31 on the second surface 30B. The solder paste 35 flowing into the through-hole 31 solidifies upon cooling, becoming... Figure 11 Solder 36 is shown. Solder 36 electrically connects the through-hole 31 to the lead 12 of the first electronic component 10.

[0073] In step S3, the solder ball 22 is also heated by reflow soldering. Through heating, the solder ball 22 and... Figure 7 The pads 32 shown are bonded.

[0074] In the third step S3, the solder ball 22 is heated, thereby allowing its height to become lower than the height h1 before the third step S3. As described above, the viscosity of the solder ball 22 can be a high viscosity, higher than the viscosity of the solder paste 35. Because the solder ball 22 has a high viscosity, even if its height is lower than height h1 during the third step S3, it can maintain a viscosity higher than h1. Figure 10 The height h2 of the solder paste 35 shown is higher than the height h2 of the solder paste 35. In the implementation of the third step S3, the height of the solder ball 22 is maintained at a height higher than the height h2 of the solder paste 35, thereby ensuring insulation between the second electronic component 20 and the solder paste 35. Therefore, in the aforementioned second step, even as... Figure 9 As shown, when viewed from above, a portion of the second electronic component 20 overlaps with a portion of the solder paste 35, and during the implementation of the third step S3, insulation between the second electronic component 20 and the solder paste 35 can also be ensured.

[0075] Here, as Figure 9 As shown, when viewed from above, in the second electronic component 20, the end of the base portion 21 on the solder paste 35 side can overlap with the solder paste 35. Therefore, as described above, it is also possible that only the solder balls 22A located on the base portion 21 on the solder paste 35 side can overlap with the solder paste 35. Figure 5 The height of the two solder balls 22A at the two corners of the generally rectangular base portion 21 shown is higher than the height h2 of the solder paste 35. In this case, during the implementation of the third step S3, the height of the two solder balls 22A located at the two corners of the base portion 21 can be maintained at a height higher than h2. Figure 10 The height h2 of the solder paste 35 shown is higher than that of the solder paste 35. The height of the two solder balls 22A located at the two corners of the base portion 21 is maintained at a height higher than that of the solder paste 35, thereby reducing the possibility of the end of the base portion 21 on the solder paste 35 side contacting the solder paste 35. By reducing the possibility of the end of the base portion 21 on the solder paste 35 side contacting the solder paste 35, insulation between the second electronic component 20 and the solder paste 35 can be ensured.

[0076] In the implementation of step S3, when solder ball 22A includes a metal core or a resin core, the height of solder ball 22A can be maintained at least at the height of the metal core or resin core. Since the height of solder ball 22A is maintained at least at the height of the metal core or resin core, the height of solder ball 22A can be maintained more reliably than... Figure 10 The height h2 of the solder paste 35 shown is higher. With this structure, the insulation between the second electronic component 20 and the solder paste 35 can be more reliably ensured during the implementation of the third process S3.

[0077] Here, as Figure 9As shown, when viewed from above, in the second electronic component 20, the end of the base portion 21 on the solder paste 35 side can overlap with the solder paste 35. Therefore, as described above, it is also possible that only the solder balls 22A located on the base portion 21 on the solder paste 35 side can overlap with the solder paste 35. Figure 5 The two solder balls 22A at the two corners of the generally rectangular base portion 21 shown comprise a metal core or a resin core. In this case, during the implementation of the third step S3, the height of the two solder balls 22A located at the two corners of the base portion 21 can be maintained at least at the height of the metal core or resin core. Because the height of the two solder balls 22A located at the two corners of the base portion 21 is maintained at least at the height of the metal core or resin core, it is possible to more reliably maintain a height higher than that of the metal core or resin core. Figure 10 The height h2 of the solder paste 35 shown is higher. With this structure, the possibility of the end of the base portion 21 on the solder paste 35 side coming into contact with the solder paste 35 can be reduced. By reducing the possibility of the end of the base portion 21 on the solder paste 35 side coming into contact with the solder paste 35, insulation between the second electronic component 20 and the solder paste 35 can be ensured.

[0078] In the third process S3, the reflow soldering is performed... Figure 7 When heating the first surface 30A shown, the area where the via 31 is located may be heated before the area where the solder pad 32 is located. For example, in the third step S3, when heating the first surface 30A, the first area 33 may be heated before the second area 34. For example, by heating the first area 33 before the second area 34, the solder paste 35 can melt and flow into the via 31 before the solder ball 22 is heated. Since the solder paste 35 flows into the via 31 before the solder ball 22 is heated, the possibility of the second electronic component 20 contacting the solder paste 35 can be reduced during the implementation of the third step S3. By reducing the possibility of the second electronic component 20 contacting the solder paste 35, the insulation between the second electronic component 20 and the solder paste 35 can be more reliably ensured.

[0079] In the third process S3, the reflow soldering is performed... Figure 7 When the first surface 30A is heated, the temperature at which the area containing the solder pad 32 is heated can be higher than the temperature at which the area containing the via 31 is heated. For example, in the third step S3, when the first surface 30A is heated, the temperature at which the second region 34 is heated can be higher than the temperature at which the first region 33 is heated. With this structure, as described above, the solder paste 35 melts and flows into the via 31 before the solder ball 22 is heated. As described above, the solder paste 35 flows into the via 31 before the solder ball 22 is heated, thereby reducing the possibility of the second electronic component 20 coming into contact with the solder paste 35. As described above, the insulation between the second electronic component 20 and the solder paste 35 can be more reliably ensured.

[0080] <Step 4>

[0081] In step S4, the following was implemented: Figure 11 The printed circuit board 30 is flipped up and down after step S3, as shown in step S4. Figure 12 As shown, solder paste 37 is applied to the second surface 30B of the printed circuit board 30, on the side where the first electronic component 10 is not disposed, including the first surface 30A and the second surface 30B. The solder paste 37 can be applied to the pads on the second surface 30B. The solder paste 37 can be applied through a metal mask. In the fourth step S4, after the solder paste 37 is applied, the third electronic component 40 is disposed on the solder paste 37.

[0082] The third electronic component 40 can be arranged on the second surface 30B opposite to the first electronic component 10. By arranging the third electronic component 40 opposite to the first electronic component 10, the area of ​​the printed circuit board 30 can be reduced compared to the case where the third electronic component 40 is not opposite to the first electronic component 10. Since the area of ​​the printed circuit board 30 is reduced, the finished electronic module can be miniaturized.

[0083] The third electronic component 40 can be any type of electronic component. For example, the third electronic component 40 can be a chip inductor, chip capacitor, diode, or chip resistor, etc. The third electronic component 40 can be a protective element used to prevent surge current from entering the printed circuit board 30.

[0084] When the third electronic component 40 is a protective element for preventing surge current from entering the printed circuit board 30, and the first electronic component 10 is a connector for connecting to an external device, the third electronic component 40 can be disposed together with the first electronic component 10 at the end of the printed circuit board 30. By disposing the third electronic component 40, which serves as a protective element, at the end of the printed circuit board 30, surge current can be more effectively prevented from entering the interior of the printed circuit board 30 in the finished electronic module.

[0085] <Step 5>

[0086] In step S5, reflow soldering is performed. In step S5, reflow soldering is used to... Figure 12 The second surface 30B of the printed circuit board 30 shown is heated.

[0087] In step S5, reflow soldering is used to... Figure 12 In step S4 shown, the solder paste 37 applied melts. The molten solder paste 37 is cooled and solidified, thus becoming... Figure 13 Solder 38 is shown.

[0088] Thus, according to the manufacturing method of the electronic module involved in this embodiment, in the second step S2, as... Figure 9 As shown, when viewed from above, at least a portion of the second electronic component 20 overlaps with a portion of the solder paste 35. Since the height h1 of the solder ball 22A is higher than the height h2 of the solder paste 35, insulation between the second electronic component 20 and the solder paste 35 can be ensured, as described above. With this structure, the area of ​​the printed circuit board 30 can be reduced, enabling miniaturization of the finished electronic module.

[0089] Furthermore, in this embodiment, the first electronic component 10 can be a component that can be mounted using through-hole reflow soldering. Since the first electronic component 10 is a component that can be mounted using through-hole reflow soldering, as explained below, it is possible to... Figure 12 The third electronic component 40 shown is disposed on the second surface 30B of the printed circuit board 30 in a manner opposite to the first electronic component 10.

[0090] For example, consider the case where a first electronic component 10 is mounted onto a printed circuit board 30 via solder flow. During solder flow, it is necessary to ensure that the molten solder flows from... Figure 10 The printed circuit board 30 shown has leads 12 attached to its second surface 30B. During solder flow, molten solder may sometimes adhere to portions of the second surface 30B other than the leads 12, such as between the two leads 12. If molten solder adheres to portions of the second surface 30B other than the leads 12, it may be difficult to mount the third electronic component 40 on the second surface 30B.

[0091] In contrast, by using through-hole reflow soldering to mount the first electronic component 10, the possibility of solder adhering to parts of the second surface 30B other than the lead 12 can be reduced. This structure allows for... Figure 12 The third electronic component 40 shown is disposed on the second surface 30B of the printed circuit board 30 in a manner opposite to the first electronic component 10.

[0092] (Other examples of manufacturing methods for electronic modules)

[0093] The execution order of steps S1 to S5 in the manufacturing method of the electronic module of the present invention is not limited to the order of step S1, step S2, step S3, step S4, and step S5. As another example, as explained below, the execution order of steps S1 to S5 in the manufacturing method of the electronic module may be step S4, step S5, step S1, step S2, and step S3. In other examples, step S4 and step S5 are performed before steps S1 to S3. In other words, in other examples, steps S4 and S5 are performed before the formation of… Figure 11 Before the solder 36 shown, steps S4 and S5 are performed. This structure reduces the possibility of the solder 36 melting in step S5.

[0094] <Step 4>

[0095] In the fourth step S4 involved in other examples, in Figure 12 Solder paste 37 is applied to the second surface 30B of the printed circuit board 30 shown. Similarly, the solder paste 37 can be applied via a metal mask. In the fourth step involved in other examples, also as described above, after the solder paste 37 is applied, a third electronic component 40 is disposed on top of the solder paste 37.

[0096] In the fourth step S4 involved in other examples, the third electronic component 40 is on the second surface 30B with... Figure 6 The first region 33 of the first surface 30A shown is configured in a relative manner.

[0097] <Step 5>

[0098] In the fifth step S5 involved in other examples, the same method as described above is used, with reflow soldering... Figure 12 The second surface 30B of the printed circuit board 30 shown is heated. In the fifth step S5 described in other examples, similarly as above, the solder paste 37 applied in the fourth step S4 is melted by reflow soldering. The molten solder paste 37 can then be solidified to form… Figure 13 Solder 38 is shown.

[0099] <Step 1>

[0100] In the first step S1 of other examples, after the fifth step S5 is performed... Figure 12 The printed circuit board 30 shown is flipped vertically. In the first process S1 involved in other examples, it is also referred to above. Figure 7 as well as Figure 8 As described above, solder paste 35 is also applied to the through-holes on the first surface 30A of the printed circuit board 30. In the first step S1 involved in other examples, the solder paste 35 can also be applied via a metal mask, similarly to the above.

[0101] <Step 2>

[0102] In the second step S2 involved in other examples, the same applies. Figure 9 as well as Figure 10 As described above, the first electronic component 10 and the second electronic component 20 are disposed on the same first surface 30A of the printed circuit board 30.

[0103] <Step 3>

[0104] In the third step S3 involved in other examples, the same applies as described above. Figure 10 as well as Figure 11 As described above, the first surface 30A of the printed circuit board 30 is heated by reflow soldering. As described above, by heating the first surface 30A by reflow soldering, the solder paste 35 melts and flows into the through-hole 31. As described above, the solder paste 35 solidifies to become... Figure 11 The solder 36 is shown. Additionally, as described above, the first surface 30A is heated by reflow soldering, thereby causing the solder ball 22 to... Figure 7 The pads 32 shown are bonded.

[0105] The other effects and structures of the electronic module manufacturing methods involved in the other examples are the same as those of the electronic module manufacturing methods described above.

[0106] (Structure of the electronic module)

[0107] Figure 13 This is a side view of the printed circuit board 30 after step S5 has been performed. The electronic module 1 includes a first electronic component 10, a second electronic component 20, a printed circuit board 30, and a third electronic component 40. The leads 12 of the second electronic component 20 are connected to solder 36... Figure 6 The through-hole 31 of the printed circuit board 30 shown is electrically connected. The solder balls 22 of the second electronic component 20 are connected to... Figure 6 The pads 32 of the printed circuit board 30 shown are bonded.

[0108] The distance D1 between the first electronic component 10 and the second electronic component 20 is shorter than... Figure 9 The length L shown is the specified length. Length L is the length by which the solder paste 35 extends beyond the main body 11. In the second process S2 described above, as... Figure 9 As shown, when viewed from above, a portion of the second electronic component 20 overlaps with a portion of the solder paste 35, thereby making the distance D1 shorter than the length L. By making the distance D1 shorter than the length L, the electronic module 1 can be miniaturized.

[0109] Here, the length L can be determined by the amount V of each solder paste 35 applied in the first step S1. s The shape of each opening of the metal mask used in step S1, and Figure 9 The distance d between the main body 11 and the through hole 31 shown is determined. For example, the length L can be expressed by formula (1).

[0110] L=(V s / Mh / Mw) / 2-d (1)

[0111] In formula (1), the height Mh is the height of the opening of each metal mask. The width Mw is the width of the opening of each metal mask.

[0112] For example, in formula (1), the amount V of solder paste 35 s The calculation example shown in formula (2) below is 1.84mm. 3 Additionally, the height Mh of the opening in the metal mask is 0.15 mm, the width Mw of the opening is 2.4 mm, and the distance d is 1.4 mm. In this case, the length L can be 1.15 mm.

[0113] For example, in formula (1), the amount V of solder paste 35 s As shown in the calculation example of formula (3) below, it is 1.75mm. 3 Additionally, the height Mh of the opening in the metal mask is 0.15 mm, the width Mw of the opening is 2.4 mm, and the distance d is 1.4 mm. In this case, the length L can be 1.03 mm.

[0114] Amount of solder paste V s This can be considered as the sum of the volume V1 of each through-hole 31 and the volume V2 of the opening of the metal mask. In this case, the amount of solder paste V... s It can be represented by the following formula (2).

[0115] V s =V1+V2 (2)

[0116] For example, in formula (2), when the volume V1 is 0.27 mm 3 The volume V2 is 1.57mm. 3 In the case of quantity V s It is 1.84mm 3 .

[0117] Amount of solder paste V s The amount V3 of solder 38 can also be calculated using the percentage P of the resin component (flux) contained in the solder paste 35. The amount V3 of solder 38 can also be calculated using the length A and radius R1 of the through-hole 31, the length B and radius R2 of the lead 12 of the first electronic component 10, and the radius R3 of the pad on the second surface 30B. In this case, the amount V of solder paste... s It can be represented by the following formula (3).

[0118] V s =[(R1 2 -R2 2 )×A×π+{R3 2 ×(BA)×π / 3}]×100 / (100-P)(3)

[0119] In formula (3), {(R1 2 -R2 2 The term {R3} can correspond to the amount of solder 38 in the through hole 31. 2 The term ×(BA) / 3} corresponds to the amount of solder 38 attached to the second surface 30B. In formula (3), it is assumed that the shape of the solder 38 attached to the second surface 30B is a solder foot shape. π is pi. In addition, the length A of the through hole 31 is the same as the thickness of the printed circuit board 30.

[0120] For example, in formula (3), let length A be 1.6 mm, radius R1 be 0.5 mm, length B be 2 mm, radius R2 be 0.35 mm, and radius R3 be 0.75 mm. Also, let π be 3.14 and percentage P be 50%. In this case, the amount V of solder paste 35 is... s It is 1.75mm 3 .

[0121] In electronic module 1, the third electronic component 40 is arranged on the second surface 30B opposite to the first electronic component 10. That is, the third electronic component 40 and the first electronic component 10 are opposite each other across the printed circuit board 30. By arranging the third electronic component 40 opposite to the first electronic component 10, as described above, the area of ​​the printed circuit board 30 can be reduced compared to the case where the third electronic component 40 is not arranged opposite to the first electronic component 10.

[0122] In electronic module 1, the height h3 of solder ball 22A can be greater than or equal to a specified height. The specified height can be approximately the height of the opening of the metal mask used in the first process S1. As described above, the implementation... Figure 10 The height h1 of the solder ball 22A before the third step S3 is higher than the height h2 of the solder paste 35. With this structure, even if the height of the solder ball 22A decreases during the implementation of the third step S3, the height h3 of the solder ball 22A after the implementation of the third step S3 can still be greater than or equal to the height h2 of the solder paste 35, that is, greater than or equal to the height of the opening of the metal mask. As mentioned above, the height of the opening of a typical metal mask used in the first step S1 is approximately 0.1mm to 0.15mm. Therefore, the specified height can be approximately 0.1mm to 0.15mm. In this case, the height h3 of the solder ball 22A can be higher than approximately 0.1mm to 0.15mm. Furthermore, the height h3 of the solder ball 22A can be achieved through… Figure 10 The height h1 of the solder ball 22A shown before performing the third process S3 is... Figure 3 The diameter of the pad 32 shown is used to determine this.

[0123] (Electronic components involved in the comparative example)

[0124] Figure 14 This is a top view of the printed circuit board 30 after the second process 32 involved in the comparative example has been performed. Figure 14 The structure shown is equivalent to Figure 10 The structure shown.

[0125] In the second process S2 involved in the comparative example, the second electronic component 20X is disposed on the printed circuit board 30. The second electronic component 20X has solder balls 22X. The height hx of the solder balls 22X is approximately the same as the height h2 of the solder paste 35.

[0126] In the second process S2 of the comparative example, the height hx of the solder ball 22X is approximately the same as the height h2. Therefore, if the second electronic component 20 is not arranged in a way that prevents it from overlapping with the solder paste 35, the solder paste 35 may sometimes adhere to the base portion 21 of the second electronic component 20. That is, in the second process S2 of the comparative example, the second electronic component 20 needs to be arranged in a way that prevents it from overlapping with the solder paste 35. Therefore, the distance between the second electronic component 20 and the first electronic component 10 can be a distance D2. The distance D2 is longer than... Figure 9 The length L shown is...

[0127] In contrast, such as Figure 13 As shown, in the electronic module 1 according to this embodiment, the distance D1 between the first electronic component 10 and the second electronic component 20 is shorter than a predetermined length. Figure 9 The length L is shown. With this structure, as described above, the electronic module 1 can be miniaturized. Because the electronic module 1 is miniaturized, the electronic device having the electronic module 1 can also be miniaturized.

[0128] Those skilled in the art will understand that the present invention can be implemented in other prescribed ways besides the embodiments described above without departing from its spirit or essential characteristics. Therefore, the foregoing description is illustrative and not limiting. The scope of the invention is defined not by the foregoing description but by the appended claims. All modifications within their equivalent scope are included therein.

[0129] For example, the configuration and number of the above-mentioned structural parts are not limited to the contents shown in the above description and accompanying drawings. The configuration and number of each structural part can be arbitrarily configured as long as its function can be achieved.

[0130] Explanation of the label

[0131] 1 Electronic Module

[0132] 10. Electronic Component No. 1

[0133] 11 Main Body

[0134] 12 leads

[0135] 20. Second electronic component

[0136] 21. Base section

[0137] 22, 22A solder balls

[0138] 23 components

[0139] 30 Printed substrate

[0140] 30A Page 1

[0141] 30B Page 2

[0142] 31 Through Hole

[0143] 32 pads

[0144] 33 Area 1

[0145] 34 Area 2

[0146] 35 and 37 solder paste

[0147] Solder 36, 38

[0148] 40 Third Electronic Component

Claims

1. A method for manufacturing an electronic module, comprising the following steps: The first step is to apply solder paste over the through-holes of the printed circuit board. In the second step, a first electronic component with leads and a second electronic component with surface-mount connectors are disposed on the same side of the printed circuit board. In this step, the leads are inserted into the through-holes to assemble the first electronic component, and the second electronic component is disposed such that the connectors are connected to the bonding pads of the printed circuit board. The third step involves reflow soldering to melt the solder paste. The height of the connecting component located on the side of the first electronic component is higher than the height of the solder paste. In the second process, when viewed from above, at least a portion of the second electronic component overlaps with a portion of the solder paste.

2. The method for manufacturing an electronic module according to claim 1, wherein, After performing the third step, the following steps are also included: In the fourth step, after applying solder paste to the side of the printed circuit board not containing the first electronic component, the third electronic component is positioned opposite the first electronic component; and In the fifth step, the solder paste applied in the fourth step is melted by reflow soldering.

3. The method for manufacturing an electronic module according to claim 2, wherein, The first electronic component is a connector for connecting to external devices. The third electronic component is a protective element used to prevent surge current from entering the printed circuit board. The region where the through hole is located is positioned such that at least a portion of the outer periphery of the region is adjacent to or connected to the outer periphery of the printed circuit board.

4. The method for manufacturing an electronic module according to any one of claims 1 to 3, wherein, In the third step, the area where the via is located is heated first, compared to the area where the pad is located.

5. The method for manufacturing an electronic module according to any one of claims 1 to 3, wherein, The connecting component located at least on the side of the first electronic component is a solder ball.

6. The method for manufacturing an electronic module according to claim 5, wherein, The welding ball contains a metal core or a resin core.

7. The method for manufacturing an electronic module according to claim 5, wherein, The second electronic component also has a base portion that is roughly rectangular when viewed from above. The two solder balls located at the two corners of the generally rectangular base portion when viewed from above each contain a metal core or a resin core.

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