Solder molded article and method for joining solder molded article

Abstract

Provided are a solder molded article and a method for joining the solder molded article which are capable of improving work efficiency and improving heat dissipation of an electronic component mounted on a substrate. This solder molded article is inserted into a plurality of holes (23) formed in a substrate (2) on which an electronic component (1) is mounted. The present invention includes: a plurality of pin parts (31) which are formed at positions corresponding to holes (23) in a substrate (2) and which are inserted into the holes (23) in the substrate (2); and a support part (32) which supports the plurality of pin parts (31). The plurality of pin parts (31) and the support part (32) contain solder.

Description

Solder molded product and bonding method for solder molded product

[0001] The present invention relates to a solder molded product bonded to a substrate on which electronic components are mounted, and to a bonding method for the solder molded product.

[0002] Electronic components such as semiconductors are mounted on substrates of electronic circuits. Electronic components generate heat from themselves or from heating elements included therein. Heat of the electronic components is dissipated by escaping from the mounting surface of the substrate on which the electronic components are mounted to the back surface of the substrate. However, the substrate itself has low thermal conductivity. Accordingly, as disclosed in Patent Document 1, a technique has been proposed in which holes such as through-holes provided in a substrate are filled with paste-like solder, and heat from electronic components is released from the mounting surface to the back surface of the substrate via the solder.

[0003] Japanese Patent No. 4746990

[0004] However, when filling paste-like solder into the holes of the substrate, voids may be formed, which may lead to decreased thermal conductivity. In addition, since the holes of the substrate are small, the workability of filling the paste-like solder into the holes of the substrate is poor.

[0005] The present invention has been made to solve the above problems, and an object of the present invention is to provide a solder molded product and a bonding method for the solder molded product that can improve work efficiency and enhance the heat dissipation performance of electronic components mounted on a substrate.

[0006] The solder molded product of the present invention is a solder molded product inserted into a plurality of holes formed in a substrate on which electronic components are mounted, comprising: a plurality of pin parts formed at positions corresponding to the holes of the substrate and inserted into the holes of the substrate; and a support part that supports the plurality of pin parts, wherein the plurality of pin parts and the support part are made of a solder component.

[0007] Furthermore, the present invention relates to a method for joining solder-formed articles, comprising joining solder-formed articles to a plurality of holes formed in a substrate on which electronic components are mounted, and comprising an insertion step of inserting the solder-formed article containing solder components into the holes of the substrate, and a melting step of melting the solder-formed article after the insertion step to fill the holes, wherein the solder-formed article has a plurality of pin portions formed at positions corresponding to the holes in the substrate, and support portions that support the plurality of pin portions, the outer diameter of the pin portions being shorter than the inner diameter of the holes in the substrate in the state before the melting step, the insertion step of inserting the pin portions into the holes in the substrate, and the melting step of allowing a part of the support portions to flow into the holes in the substrate to fill the holes in the substrate.

[0008] According to the present invention, it is possible to obtain a soldered product and a method for joining soldered products that can improve work efficiency and enhance the heat dissipation of electronic components mounted on a substrate.

[0009] This is a schematic diagram showing electronic components mounted on a circuit board. This is a perspective view showing the configuration of a solder-formed product of an embodiment. This is a schematic diagram showing a solder-formed product inserted into a hole in a circuit board. This is a schematic diagram showing a solder-formed product in a molten state. This is a schematic diagram showing the state of a solder-formed product after molten. This is a perspective view showing the configuration of a modified solder-formed product. This is a schematic diagram showing a solder-formed product inserted into a hole in a circuit board. This is a schematic diagram showing a solder-formed product in a molten state. This is a schematic diagram showing a solder-formed product of another embodiment joined to a circuit board.

[0010] [Embodiments] Solder molded products according to embodiments will be described with reference to the drawings. In each drawing, thickness, dimensions, positional relationships, ratios, or shape may be emphasized for ease of understanding, and the present invention is not limited to such emphasis.

[0011] Figure 1 is a schematic diagram showing an electronic component 1 mounted on a substrate 2. As shown in Figure 1, the electronic component 1 is placed on the substrate 2. Examples of electronic components 1 include semiconductors, reactors, and transformers. The electronic component 1 has a heat-generating element and generates heat. The heat generated in the electronic component 1 is dissipated through the substrate 2.

[0012] The substrate 2 is a plate-shaped member for connecting electronic components 1 to a circuit. The substrate 2 is, for example, a printed circuit board. Electronic components 1 are joined to the circuit on the substrate 2 by soldering. The substrate 2 has a mounting surface 21 on which the electronic components 1 are placed, and a solder insertion surface 22 on the opposite side from the mounting surface 21.

[0013] As shown in Figure 1, the substrate 2 has a plurality of holes 23 formed therein. The holes 23 are circular. The holes 23 are, for example, vias or through-holes. In this embodiment, the holes 23 are vias, and the inner diameter of the holes 23 is coated with copper plating about 20 μm thick. The holes 23 extend from the mounting surface 21 to the solder insertion surface 22 and penetrate the substrate 2. Solder molded products 3 are inserted into and filled in these holes 23.

[0014] Figure 2 is a perspective view of the solder-molded product 3. The solder-molded product 3 is positioned on the solder insertion surface 22 side of the substrate 2. The solder-molded product 3 has a pin portion 31 and a support portion 32. The pin portion 31 of the solder-molded product 3 is inserted into the hole 23 of the substrate 2. After the pin portion 31 of the solder-molded product 3 is inserted into the hole 23 of the substrate 2, the solder-molded product 3 is melted and solidified to fix it to the substrate 2.

[0015] The pin portion 31 and the support portion 32 are made of solder material. Solder material refers to an alloy mainly composed of tin. In addition to tin, solder material may also contain zinc, silver, antimony, lead, indium, bismuth, nickel, gold, cobalt, and germanium. Main component of tin means that the tin content is higher than that of other materials.

[0016] Multiple pin portions 31 are provided. The multiple pin portions 31 are arranged to correspond to the positions of the holes 23 in the substrate 2. The pin portions 31 are inserted into the holes 23. The pin portions 31 correspond to the shape of the holes 23 and are cylindrical in shape. However, the shape of the pin portions 31 does not need to correspond to the shape of the holes 23 in the substrate 2, as long as they can be inserted into the holes 23.

[0017] Figure 3 shows the solder-molded product 3 inserted into the hole 23. Figure 3 shows the state before the solder-molded product 3 is melted, which will be described later. The outer diameter d1 of the pin portion 31 is smaller than the inner diameter d2 of the hole 23, as shown in Figure 3. Also, the length h1 of the pin portion 31 is shorter than the length h2 of the hole 23. The length h1 of the pin portion 31 is the distance from the interface between the pin portion 31 and the support portion 32 to the extended tip surface of the pin portion 31. The length h2 of the hole 23 is the length from the mounting surface 21 to the solder insertion surface 22.

[0018] The support portion 32 is a plate-shaped member. The thickness of the support portion 32 is, for example, about 0.5 mm to 1.0 mm. The support portion 32 supports a plurality of pin portions 31. The support portion 32 and the pin portions 31 are integrally molded, and the pin portions 31 rise from the wide surface of the support portion 32. When the solder-molded product 3 is melted, a part of the support portion 32 fills the hole 23 in the substrate 2.

[0019] Next, a method for joining the solder-molded product 3 to the substrate 2 will be described. First, a solder-molded product consisting of multiple pin portions 31 and support portions 32 is manufactured. When manufacturing the solder-molded product 3, the arrangement of holes 23 in the substrate 2 is determined in advance, and the pin portions 31 are formed to correspond to the arrangement of holes 23 in the substrate 2. The solder-molded product 3 is manufactured as a single-piece molded product in which the multiple pin portions 31 and support portions 32 are integrated.

[0020] Once the solder-formed product 3 is manufactured, the process moves to the insertion step, in which the pin portion 31 of the solder-formed product 3 is inserted into the hole 23 of the substrate 2. First, solder is applied to the mounting surface 21 of the substrate 2 to bond the electronic component 1 to the mounting surface 21. With the mounting surface 21 of the substrate 2 facing upwards, the electronic component 1 is placed on it. Then, a reflow process is performed to melt the solder applied to the mounting surface 21. Through the reflow process, the electronic component 1 is bonded to the mounting surface 21 of the substrate 2.

[0021] After the reflow process, the process moves to the insertion process, in which the solder-formed product 3 is inserted into the hole 23 of the substrate 2. First, as shown in Figure 3, the substrate 2 on which the electronic components 1 are bonded is turned over so that the solder insertion surface 22 faces upward.

[0022] The pin portion 31 is then inserted into the hole 23 from the solder insertion surface 22 side of the substrate 2. Since multiple pin portions 31 are formed at corresponding positions in the holes 23 of the substrate 2, multiple pin portions 31 are inserted into each hole 23 at once.

[0023] Since the outer diameter d1 of the pin portion 31 is smaller than the inner diameter d2 of the hole 23 in the substrate 2, it does not contact the inner surface of the hole 23. Also, since the length h1 of the pin portion 31 is shorter than the length h2 of the hole 23 in the substrate 2, it does not protrude from the mounting surface 21 of the substrate 2. Therefore, as shown in Figure 3, when the pin portion 31 is inserted into the hole 23 in the substrate 2, it does not completely fill the space of the hole 23.

[0024] Once the insertion of the pin portion 31 of the solder-molded product 3 into the hole 23 of the substrate 2 is complete, the solder-molded product 3 moves on to the melting process. In the melting process, the solder-molded product 3, with the pin portion 31 inserted into the hole 23 of the substrate 2, is placed into a furnace equipped with a heating element such as a heater. When placed in the furnace, as shown in Figure 3, the solder-molded product 3 is positioned above the substrate 2. Here, the vertical direction is parallel to the direction of gravity, with the direction in which gravity acts being downward and the direction against gravity being upward. The pin portion 31 and support portion 32 of the solder-molded product 3 are melted. The molten pin portion 31 fills every corner of the hole 23 of the substrate 2.

[0025] However, the outer diameter d1 of the pin portion 31 is smaller than the inner diameter d2 of the hole 23 in the substrate 2, and its length h1 is also shorter than the length h2 of the hole 23. Therefore, the pin portion 31 alone cannot fill the entire space of the hole 23 in the substrate 2. However, the solder-molded product 3 has a support portion 32. Then, as shown in Figure 4, a portion of the molten support portion 32 flows into the hole 23 in the substrate 2.

[0026] In particular, the support portion 32 supports multiple pin portions 31, and the holes 23 in the solder insertion surface 22 of the substrate 2 are covered by the support portion 32. Therefore, the molten support portion 32 easily flows into the holes 23 of the substrate 2 through the gaps between the pin portions 31 due to its own weight. Also, since the solder molded product 3 is placed above the substrate 2 during the melting process, the molten pin portions 31 move toward the mounting surface 21 of the substrate 2 inside the holes 23 due to their own weight. Therefore, a space is easily created on the solder insertion surface 22 side of the holes 23, and the molten support portion 32 easily flows into the holes 23. Thus, as shown in Figure 5, the holes 23 of the substrate 2 are completely filled by the pin portions 31 and a part of the support portion 32 of the solder molded product 3. Then, the molten solder molded product 3 is solidified and bonded to the substrate 2.

[0027] In this way, a portion of the support portion 32 is filled into the hole 23 of the substrate 2. As a result, the volume of the support portion 32 after the melting process is smaller than the volume before the melting process, the volume of the pin portion 31 is larger, and the outer diameter of the pin portion 31 becomes the same as the inner diameter d2 of the hole 23 of the substrate 2.

[0028] In this embodiment, the electronic component 1 is bonded to the mounting surface 21 of the substrate 2 before inserting the solder-formed product 3 into the hole 23 of the substrate. However, the solder-formed product 3 may be inserted into the hole 23 of the substrate 2 first. In this case, first, the solder insertion surface 22 of the substrate 2 is turned upwards, the solder-formed product 3 is inserted into the hole 23 of the substrate 2, and the solder-formed product 3 is melted to fill the hole 23 of the substrate 2 with the solder-formed product 3. Then, the substrate 2 is turned over so that the mounting surface 21 of the substrate is turned upwards, and the electronic component 1 is placed on the mounting surface 21 of the substrate 2, which has solder applied to it. Then, the solder applied to the mounting surface 21 is melted by a reflow process, and the electronic component 1 is bonded to the mounting surface 21 of the substrate 2.

[0029] [Effect] As described above, the solder-molded product 3 of this embodiment is a solder-molded product 3 that is inserted into a plurality of holes 23 formed in a substrate 2 on which an electronic component 1 is mounted. The solder-molded product 3 comprises a plurality of pin portions 31 formed at positions corresponding to the holes 23 in the substrate 2 and inserted into the holes 23 in the substrate 2, and a support portion 32 that supports the plurality of pin portions 31, and the plurality of pin portions 31 and the support portion 32 are made of solder material.

[0030] This allows multiple pin portions 31 of the solder-molded product 3 to be inserted into the holes 23 of the substrate 2 at once. Therefore, the efficiency of inserting the solder-molded product 3 into the holes 23 of the substrate 2 is increased.

[0031] Furthermore, the solder-formed product 3, which is made of solder components, is then melted and fills the holes 23 in the substrate 2. Since the electronic component 1 generates heat, the heat generated from the electronic component 1 is dissipated through the substrate 2, and the solder-formed product 3 that fills the holes 23 in the substrate 2 can serve as a heat dissipation path, allowing the heat from the electronic component to be dissipated.

[0032] In particular, the solder-formed product 3 is formed before being inserted into the hole 23 of the substrate 2. The solder-formed product 3 is then inserted into the hole 23 of the substrate 2 and subsequently melted to fill the hole 23 with the solder-formed product 3. In the conventional technique, when paste-like solder is used to fill the hole 23, voids are likely to form, potentially resulting in low thermal conductivity. On the other hand, in this embodiment, the pin portion 31 and support portion 32 inserted into the hole 23 of the substrate 2 are melted to fill the hole 23, thus reducing the possibility of void formation compared to when paste-like solder is used. As a result, thermal conductivity is high and heat dissipation is excellent.

[0033] Furthermore, because the holes 23 in the substrate 2 are small, filling them with paste-like solder, as in conventional technology, is time-consuming and inefficient. However, in this embodiment, the holes 23 in the substrate 2 can be filled by inserting the solder-molded product 3 into the holes 23 in the substrate 2 and then melting the solder-molded product 3, thus improving work efficiency.

[0034] Furthermore, in conventional technology, there is a method of improving heat dissipation by press-fitting copper pins made of copper into vias formed in holes 23 of the substrate 2, but there is a risk of damaging the substrate 2 or damaging the copper plating applied to the vias during press-fitting. On the other hand, in this embodiment, the solder-molded product 3 is melted and used to fill the holes 23 of the substrate 2, so damage to the substrate 2 and damage to the copper plating of the vias can be prevented.

[0035] Furthermore, in the case of vias in the holes 23 of substrate 2 that are copper-plated, in a multilayer substrate, the copper-plated portion of the via was used as a current path to supply current to each layer of substrate 2. However, since the copper plating is only about 20 μm thick, the amount of current that can be supplied is limited, and when supplying a large current, the number of vias increases, which can lead to larger substrates and constraints on the substrate design.

[0036] However, in this embodiment, the holes 23 in the substrate 2 are filled with the solder-molded product 3. Therefore, current can also flow through the parts filled with solder components, which reduces electrical resistance, prevents the substrate 2 from becoming larger, and suppresses design constraints on the substrate 2.

[0037] The outer diameter of the pin portion 31 is smaller than the inner diameter d2 of the hole 23 in the substrate 2. The embodiment also includes an insertion step of inserting the solder molded product 3 containing the solder component into the hole 23 in the substrate 2, and a melting step of melting the solder molded product 3 after the insertion step to fill the hole 23. In the insertion step, the pin portion 31 is inserted into the hole 23 in the substrate 2, and in the melting step, a part of the support portion 32 flows into the hole 23 in the substrate 2, filling the hole 23 in the substrate 2.

[0038] In this way, by making the outer diameter d1 of the pin portion 31 smaller than the inner diameter d2 of the hole 23 in the substrate 2, the pin portion 31 can be smoothly inserted into the hole 23 in the substrate 2, and the productivity of the insertion process is increased. Furthermore, since the pin portion 31 is held by the plate-shaped support portion 32, in the melting process, a portion of the molten support portion 32 can flow into the inside of the hole 23 in the substrate 2 and fill it. Therefore, even if the outer diameter d1 of the pin portion 31 is smaller than the inner diameter d2 of the hole 23 in the substrate 2, the solder-molded product 3 can fill every corner of the hole 23 in the substrate 2. As a result, productivity in the insertion process can be increased, and heat dissipation and conductivity can be improved.

[0039] The length h1 of the pin portion 31 is shorter than the length h2 of the hole 23 in the substrate 2. If the length h1 of the pin portion 31 were longer than the length h2 of the hole 23 in the substrate 2, the pin portion 31 would protrude from the mounting surface 21 of the substrate 2. Since the electronic component 1 is mounted on the mounting surface 21 of the substrate 2, the pin portion 31 may interfere with the electronic component 1, and there is a risk that the electronic component 1 cannot be fixed in the predetermined position on the substrate 2.

[0040] Therefore, as in this embodiment, by making the length h1 of the pin portion 31 shorter than the length h2 of the hole 23 in the substrate 2, interference between the pin portion 31 and the electronic component 1 can be prevented. Furthermore, as described above, even if the amount of the pin portion 31 is not enough to fill the entire volume of the hole 23 in the substrate 2, the molten support portion 32 can be allowed to flow into the hole 23 in the substrate 2, allowing the solder-formed product 3 to fill every corner of the hole 23 in the substrate 2. As a result, the electronic component 1 can be fixed in a predetermined position on the substrate 2, and heat dissipation and conductivity can be improved.

[0041] [Modified Version] In the above embodiment, the pin portion 31 of the solder-molded product 3 was cylindrical in shape and composed only of solder. In the modified version of the solder-molded product 3, as shown in Figure 6, the pin portion 31 has a solder portion 311 and a core portion 312.

[0042] The solder portion 311 is made of solder components. The solder portion 311 is cylindrical and has a space in its center. In this embodiment, this space is circular. A core portion 312 is provided in the center of the solder portion 311, and the solder portion 311 covers the core portion 312. The length of the solder portion 311 is less than or equal to the length h2 of the hole 23 in the substrate 2. In this embodiment, as shown in Figure 7, the solder portion 311 is the same length as the hole 23 in the substrate 2. Also, the outer diameter of the solder portion 311 is smaller than the inner diameter of the hole 23 in the substrate 2.

[0043] The core portion 312 is positioned within the internal space of the solder portion 311. That is, the core portion 312 has a shape corresponding to the internal space of the solder portion 311, and in this embodiment, it is cylindrical. The core portion 312 is made of a material with higher thermal conductivity than the solder portion 311. For example, the core portion 312 is made of copper or aluminum. Furthermore, it is preferable that the material constituting the core portion 312 is a material that does not melt during the melting process of the soldered product 3.

[0044] The length of the core portion 312 is less than or equal to the length of the hole 23 in the substrate 2. The length of the core portion 312 may be the same as or different from the length of the solder portion 311. In this embodiment, as shown in FIGS. 6 and 7, the length of the core portion 312 is the same as the length of the solder portion 311. That is, the core portion 312 has the same length as the hole 23 of the substrate 2.

[0045] In a modified example, a method for producing the molded solder product 3 includes, for example, forming the solder portion 311 by plating solder on an outer periphery of a core portion 312 separately produced from copper or the like, thereby producing the pin portion 31 in which the solder portion 311 is formed around the core portion 312. Then, holes corresponding to the pin portions 31 are formed in advance in the support portion 32, and the pin portions 31 are press-fitted into the support portion 32, thereby producing the molded solder product 3. However, the method for producing the molded solder product 3 is not limited thereto. For example, first, a molded product in which the solder portion 311 of the pin portion 31 and the support portion 32 are integrated is produced. In this state, the pin portion 31 has only the solder portion 311, and a central portion of the solder portion 311 has a space corresponding to the shape of the core portion 312. In addition, the core portion 312 is separately produced in advance from, for example, copper or the like. Then, the molded solder product 3 may be produced by press-fitting the core portion 312 into the interior of the solder portion 311.

[0046] Then, similarly to the above embodiment, the molded solder product 3 is inserted into the hole 23 of the substrate 2 from the solder insertion surface 22. At this time, the core portion 312 of the pin portion 31 is in contact with the electronic component 1. In this state, the molded solder product 3 is melted, the molten support portion 32 is caused to flow into the hole 23 of the substrate 2, and as shown in FIG. 8, the space formed between the solder portion 311 and the hole 23 of the substrate 2 is filled. That is, the outer diameter of the solder portion 311 after melting is equal to the inner diameter of the hole 23 of the substrate 2.

[0047] As described above, in the molded solder product 3 according to the modified example, the pin portion 31 includes the solder portion 311 made of a solder component, and the core portion 312 made of a member having higher thermal conductivity than the solder portion 311, wherein the solder portion 311 is provided outside the core portion 312 and covers the core portion 312. Thereby, the thermal conductivity of the pin portion 31 can be further improved.

[0048] Further, the length of the core portion 312 is equal to or less than the length h2 of the hole 23 in the substrate 2. Therefore, when the pin portion 31 is inserted into the hole 23 of the substrate 2, the core portion 312 does not protrude from the mounting surface 21. This can prevent interference between the core portion 312 and the electronic component 1.

[0049] In the above modified example, the length of the core portion 312 is set to be equal to or less than the length of the hole 23 of the substrate 2, but it is preferably the same length as the hole 23 of the substrate 2. In this case, in a state where the electronic component 1 is mounted on the mounting surface 21 of the substrate 2, when the pin portion 31 is inserted into the hole 23 of the substrate 2 from the solder insertion surface 22 of the substrate, the distal end surface of the core portion 312 is flush with the mounting surface 21 of the substrate 2 and abuts against the electronic component 1. As a result, the core portion 312 with high thermal conductivity abuts against the electronic component 1, so that heat from the electronic component 1 can be efficiently dissipated via the core portion 312 with high thermal conductivity, whereby heat dissipation performance can be further improved.

[0050] It should be noted that the core portion 312 may be longer than the length h2 of the hole 23 in the substrate 2. That is, the core portion 312 may extend to the bottom surface of the support portion 32 (the surface opposite to the surface of the support portion 32 from which the pin portion 31 extends). This can further improve heat dissipation performance.

[0051] [Other Embodiments] Although embodiments according to the present invention have been described in the present specification, these embodiments are presented by way of example and are not intended to limit the scope of the invention. The above-described embodiments can be implemented in various other forms, and various omissions, substitutions, and alterations can be made without departing from the scope of the invention. The embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and equivalents thereof.

[0052] In the above embodiment, the length h1 of the pin portion 31 is shorter than the length h2 of the hole 23 in the substrate 2, but may be the same. That is, the pin portion 31 only needs to have a length such that it does not protrude from the mounting surface 21 when the pin portion 31 is inserted into the hole 23 of the substrate 2. Even with this configuration, interference between the pin portion 31 and the electronic component 1 can be prevented.

[0053] As shown in Figure 9, a heat dissipation sheet 4 and a heat sink 5 may be provided below the support portion 32 of the soldered product 3. More specifically, the heat dissipation sheet 4 may be in contact with the surface of the support portion 32 opposite to the surface supporting the pin portion 31, and the heat sink 5 may be provided below the heat dissipation sheet 4. This further improves heat dissipation.

[0054] In the above embodiment, the reflow process for joining the electronic component 1 to the mounting surface 21 of the substrate 2 and the melting process for melting the solder-formed product 3 and filling the holes 23 in the substrate 2 with the solder-formed product 3 were performed as separate processes. However, the melting process and the reflow process may be performed simultaneously. That is, after placing the electronic component 1 on the mounting surface 21 of the substrate 2, the substrate 2 may be turned over, the solder-formed product 3 may be inserted into the holes 23 in the substrate 2, and then transported to a furnace to simultaneously melt the solder applied to the mounting surface 21 and the solder-formed product 3. This eliminates the need for a separate process to melt the solder-formed product 3, further improving work efficiency.

[0055] 1. Electronic component 2. Circuit board 21. Mounting surface 22. Solder insertion surface 23. Hole 3. Solder molded product 31. Pin part 311. Solder part 312. Core part 32. Support part 4. Heat dissipation sheet 5. Heat sink

Claims

1. A solder-molded product that is inserted into a plurality of holes formed in a substrate on which electronic components are mounted, comprising: a plurality of pin portions formed at positions corresponding to the holes in the substrate and inserted into the holes in the substrate; and a support portion that supports the plurality of pin portions, wherein the plurality of pin portions and the support portion are made of solder.

2. The solder-molded product according to claim 1, characterized in that the outer diameter of the pin portion is smaller than the inner diameter of the hole in the substrate.

3. The solder-molded article according to claim 1 or 2, characterized in that the length of the pin portion is shorter than the length of the hole in the substrate.

4. The soldered product according to claim 1 or 2, characterized in that the pin portion comprises a solder portion made of the solder component and a core portion made of a material with a higher thermal conductivity than the solder portion, the solder portion being provided on the outside of the core portion and covering the core portion.

5. The solder-molded product according to claim 4, characterized in that the core portion is less than or equal to the length of the hole in the substrate.

6. A method for joining solder-formed products to a plurality of holes formed in a substrate on which electronic components are mounted, comprising: an insertion step of inserting a solder-formed product containing solder components into the holes of the substrate; and a melting step of melting the solder-formed product after the insertion step to fill the holes, wherein the solder-formed product has a plurality of pin portions formed at positions corresponding to the holes in the substrate, and support portions that support the plurality of pin portions, wherein the outer diameter of the pin portions is smaller than the inner diameter of the holes in the substrate in the state before the melting step, the insertion step involves inserting the pin portions into the holes in the substrate, and the melting step involves allowing a part of the support portions to flow into the holes in the substrate to fill the holes in the substrate.

Images