WO2017109882A1

WO2017109882A1 - Substrate and method for manufacturing substrate

Info

Publication number: WO2017109882A1
Application number: PCT/JP2015/085970
Authority: WO
Inventors: 保明関; 純平高林; 直之牧野
Original assignee: 株式会社メイコー
Priority date: 2015-12-24
Filing date: 2015-12-24
Publication date: 2017-06-29
Also published as: JPWO2017109882A1; CN108353498A; JP6311081B2; CN108353498B

Abstract

A substrate (1) is provided with: a laminated wiring board (3) on which a plurality of conductive layers (2) are formed; a through hole (6) formed by penetrating the laminated wiring board (3); a through hole plating (7), which covers the inner wall of the through hole (6), and is electrically connected to the conductive layers (2); a metal piece (10), which is disposed on the inner side of the through hole plating (7), and is configured from a core section (8), and a film section (9) covering the whole surface of the core section (8); and an alloy film (11), which is disposed between the film section (9) and the through hole plating (7), and is formed of metals which the film section (9) and the through hole plating (7) are respectively formed of.

Description

Substrate and substrate manufacturing method

The present invention relates to a substrate, such as a printed wiring board, which has a metal piece inserted therein and has excellent large current and heat dissipation characteristics, and a method for manufacturing the substrate.

半導体 Semiconductor elements in electric circuits tend to generate more heat due to higher density and higher current. In particular, a semiconductor using Si causes malfunction and failure when the ambient temperature is 100 ° C. or higher. Examples of such heat-generating components such as semiconductor elements include switching elements such as IGBT (Insulated Gate Bipolar Transistor) and IPM (Intelligent Power Module).

¡In order to effectively cool the heat generating components, a heat dissipation path is formed so as to release the heat generated from the heat generating components toward the opposite side of the substrate. Specifically, cooling is performed by conducting heat generated from the heat-generating component to a heat sink or the like on the back side of the substrate (the side opposite to the component mounting surface (mounting surface)).

As the heat dissipation path, for example, a metal piece made of a metal having high thermal conductivity (Cu, Al, etc.) is used. This metal piece is fixed in a through hole formed in the substrate. The metal piece is fixed to the through hole by adhesion by press-fitting or plastic deformation, joining by an adhesive or solder, etc. (see, for example, Patent Document 1). When the metal piece comes into contact with the heat generating component, heat generated from the heat generating component is radiated to the outside through the metal piece (for example, columnar copper).

Japanese Patent Laid-Open No. 2-134895

However, there is a demand to use metal pieces not only for heat dissipation but also for electrical connection. Conventionally, the metal piece fixed to the through hole is merely in physical contact with the through hole, and thus electrical conduction is unstable. That is, the conductivity cannot be secured stably and reliably. For this reason, conventionally, through-hole plating formed by separately providing a through-hole for electrical conduction in a substrate and applying copper plating to the inner wall of the through-hole is used. However, such through-hole plating requires a space for the substrate, which is not preferable from the viewpoint of increasing the density of component mounting.

The present invention has been made in consideration of the above-described conventional technology, and has an object to provide a substrate having a heat dissipation characteristic and sufficient electrical conduction and a method for manufacturing the substrate.

In order to achieve the above object, in the present invention, a laminated wiring board in which a plurality of conductive layers made of a conductive material are formed, a through hole formed through the laminated wiring board, and an inner wall of the through hole are provided. Covering, through-hole plating electrically connected to the conductive layer, and disposed inside the through-hole plating, covering the metal core portion and the entire surface of the core portion, the core portion A metal piece composed of a different metal film part, and the metal part arranged between the film part and the through-hole plating, and formed of each other metal forming the film part and the through-hole plating. Provided is a substrate comprising an alloy film and a lid plating layer made of a metal material covering both surfaces of the laminated wiring board including the coating part.

Preferably, the coating portion has a two-layer structure of an inner layer that directly covers the core portion and an outer layer disposed outside the inner layer, and the core portion, the inner layer, and the outer layer are all formed of different metals. .

Preferably, the core portion is made of copper, silver, or aluminum, the outer layer is made of tin or gold, and the inner layer is made of nickel.

Further, in the present invention, a laminated wiring board forming step of forming a laminated wiring board by stacking a plurality of insulating layers made of an insulating resin material and a conductive layer formed of a conductive material as a pattern, respectively, and pressing them in the laminating direction; A through-hole plating forming step of forming a through-hole penetrating the laminated wiring board and forming a through-hole plating electrically connected to the conductive layer on the inner wall of the through-hole by performing a plating process; Forming a core part, plating the core part with a metal different from the core part to form a film part, and forming a metal piece in which the entire surface of the core part is covered with the film part A metal piece forming step, and in a state where the metal piece is inserted into the through hole and disposed in the through hole, the metal piece is pressed to expand the diameter of the metal piece, and the gold The pressing step of bringing the film portion of the piece and the through-hole plating into contact with each other, and forming the film portion and the through-hole plating by heating the contact portion between the film portion and the through-hole plating An alloy film forming step of forming an alloy film by alloying a metal is provided.

Preferably, in the metal piece forming step, the coating portion having a two-layer structure including an inner layer and an outer layer is formed by performing a two-layer plating process on the core portion, and the core portion, the inner layer, All outer layers are made of different metals.

Preferably, in the metal piece forming step, the core portion is formed of copper, silver, or aluminum, the outer layer is formed of tin or gold, and the inner layer is formed of nickel.

According to the substrate according to the present invention, the core part forming the metal piece is joined to the through-hole plating through the alloy film. Therefore, as a result, the core portion can be electrically connected to the conductive layer. Since this connection is made by an alloy layer formed by chemically reacting the coating covering the core and the through-hole plating, it is possible to ensure a stable and reliable electrical connection (conductivity). it can. That is, it is possible to obtain a substrate that has heat dissipation characteristics and can achieve sufficient electrical conduction. Further, since conductivity can be ensured through the core portion in this way, there is no need to separately form through-hole plating for electrical conduction on the laminated wiring board. For this reason, the space for forming such a through hole becomes unnecessary, and it can contribute to the high density of the component mounting in the board | substrate currently calculated | required in recent years. Further, the core portion is covered with the coating portion on both sides of the through hole in the penetrating direction. For this reason, it can prevent that a core part will be exposed and can protect a core part. Moreover, both surfaces of the laminated wiring board may be covered with a lid plating layer together with the coating portion (metal piece). Thereby, the integration of the metal piece and the laminated wiring board is strengthened, and the metal piece is surely prevented from coming out of the through hole, and the integrity as the substrate can be secured.

Further, by forming the core portion and the coating portion from different metals, the core portion can be formed from a metal having excellent electrical continuity and heat dissipation, and the coating portion can be formed from a metal that is easily alloyed. In this way, by using different metals for the core portion and the coating portion, it is possible to select an optimum metal while taking into consideration the electrical continuity and heat dissipation action according to the characteristics of each other. Furthermore, it is possible to prevent the core portion and the coating portion from being alloyed by forming the coating portion with a two-layer structure (inner layer and outer layer) made of different metals. That is, by forming the inner layer with a metal having relatively low reactivity, the inner layer is interposed between the core portion and the outer layer, so that the core portion and the outer layer are prevented from being alloyed. Furthermore, even if the inner wall surface of the through-hole plating has an uneven shape, by using a soft metal as the outer layer (the coating part if the coating part is not a two-layer structure), the outer layer (the coating part) However, since it follows corresponding to this uneven | corrugated shape, it can distribute | arrange so that a metal piece can be reliably hold | maintained in a through hole. Considering these, it is preferable that the core portion is made of any metal of copper, silver, or aluminum having high electrical conduction characteristics and heat dissipation characteristics. The outer layer is preferably made of either tin or gold having high spreading characteristics. Further, the inner layer is preferably formed of nickel having low reactivity.

Further, according to the method for manufacturing a substrate according to the present invention, in the metal piece forming step, the core portion is plated so as to cover the entire surface with the coating portion, so that the metal piece is removed in the subsequent pressing step. The core part can be protected when pressed. In the metal piece forming step, a coating portion different from the core portion is formed in advance, and in the alloy film forming step, the coating portion and the through-hole plating are alloyed. The alloy layer is formed by a chemical reaction. For this reason, stable and reliable electrical connection (conductivity) can be ensured. And since the alloy film in which stable electrical connection is ensured in this way covers the core part, the core part is joined to the through-hole plating through the alloy film as a result. Thereby, the electrical connection between a core part and a conductive layer is securable. That is, it is possible to obtain a substrate that has heat dissipation characteristics and can achieve sufficient electrical conduction.

Through the through-hole plating forming process, metal piece forming process, pressing process, and alloy film forming process, it is possible to ensure electrical continuity with the conductive layer through the core part. There is no need to form a plating. For this reason, the space for forming such a through hole becomes unnecessary, and it can contribute to the high density of the component mounting in the board | substrate currently calculated | required in recent years.

Also, a lid plating layer forming step may be performed so that both surfaces of the laminated wiring board are covered with a lid plating layer together with the coating portion (metal piece). Thereby, the integration of the metal piece and the laminated wiring board is strengthened, and the metal piece is surely prevented from coming out of the through hole, and the integrity as the substrate can be secured.

In addition, since the core part and the coating part are formed of different metals in the metal piece forming step, the core part is formed of a metal having excellent electrical continuity and heat dissipation, and the coating part is made of a metal that is easily alloyed. Can be formed. In this way, by using different metals for the core portion and the coating portion, it is possible to select an optimum metal while taking into consideration the electrical continuity and heat dissipation action according to the characteristics of each other. Furthermore, the two-layer plating process is performed in the metal piece forming process, and the coating portion is formed as a two-layer structure (inner layer and outer layer) made of different metals, thereby preventing the core portion and the coating portion from being alloyed. it can. That is, by forming the inner layer with a metal having relatively low reactivity, the inner layer is interposed between the core portion and the outer layer, so that the core portion and the outer layer are prevented from being alloyed. Furthermore, even if the inner wall surface of the through-hole plating has an uneven shape, by using a soft metal as the outer layer (the coating part if the coating part is not a two-layer structure), the outer layer (the coating part) However, since it follows corresponding to this uneven | corrugated shape, it can arrange | position so that a metal piece may be reliably hold | maintained in a through hole. Considering these, it is preferable that the core portion is made of any metal of copper, silver, or aluminum having high electrical conduction characteristics and heat dissipation characteristics. The outer layer is preferably made of either tin or gold having high spreading characteristics. Further, the inner layer is preferably formed of nickel having low reactivity.

It is a schematic sectional drawing of the board | substrate which concerns on this invention. It is a schematic sectional drawing of another board | substrate which concerns on this invention. It is a flowchart of the manufacturing method of the board | substrate which concerns on this invention. It is the schematic for demonstrating in order the manufacturing method of the board | substrate which concerns on this invention. It is the schematic for demonstrating in order the manufacturing method of the board | substrate which concerns on this invention. It is the schematic for demonstrating in order the manufacturing method of the board | substrate which concerns on this invention. It is the schematic for demonstrating in order the manufacturing method of the board | substrate which concerns on this invention. It is the schematic for demonstrating in order the manufacturing method of the board | substrate which concerns on this invention. It is the schematic for demonstrating in order the manufacturing method of the board | substrate which concerns on this invention.

As shown in FIG. 1, a substrate 1 according to the present invention has a laminated wiring board 3 called a multilayer board (including a double-sided board) in which a plurality of conductive layers 2 are formed as a main structure. In the example of FIG. 1, a so-called four-layer plate in which four conductive layers 2 are formed is shown. The conductive layer 2 is formed in each layer as a conductor pattern. An insulating layer 4 is disposed between the conductive layers 2. The insulating layer 4 is made of an insulating material such as a prepreg.

The through-hole 6 is formed in the laminated wiring board 3. The through hole 6 penetrates the laminated wiring board 3. The through hole 6 has a substantially cylindrical shape. In the plan view of the laminated wiring board 3 as viewed from above, the through hole 6 has a circular shape. A through hole plating 7 is formed on the inner wall of the through hole 6. Since the through hole plating 7 is formed in contact with the inner wall of the through hole 6, the conductive layer 2 communicating with the inner wall of the through hole 6 and the through hole plating 7 are electrically connected. For this reason, copper is preferable as the plating material. The through-hole plating 7 is formed on both surfaces of the laminated wiring board 3 and the inner wall surface of the through-hole 6.

In the through hole 6, a metal piece 10 is arranged. The metal piece 10 is formed of a metal core portion 8 and a coating portion 9 that covers the entire surface of the core portion 8. The film part 9 is made of a metal different from the core part 8. Moreover, the core part 8 is substantially cylindrical shape. Since the core portion 8 plays a role of heat dissipation and conduction of the substrate 1, a metal having excellent heat dissipation and conduction characteristics is used for the core portion 8.

The metal piece 10 is held in engagement with the through hole 6 with its diameter being expanded outward in the through hole 6. That is, the metal piece 10 is fitted in the through hole 6. Here, an alloy film 11 is disposed between the metal piece 10 and the through-hole plating 7. The alloy film 11 is formed by alloying the metals forming the film portion 9 and the through-hole plating 7.

The lid plating layer 12 is arranged on both surfaces of the laminated wiring board 3. The lid plating layer 12 covers both surfaces of the laminated wiring board 3. Since this lid plating layer 12 is formed by a plating process, metal is deposited on the surface of the laminated wiring board 3. The lid plating layer 12 covers the laminated wiring board 3 including the surface of the coating 9 exposed on the surface of the laminated wiring board 3.

By adopting the substrate 1 having the above structure, the core portion 8 forming the metal piece 10 is bonded to the through-hole plating 7 through the alloy film 11. Therefore, as a result, the core portion 8 is electrically connected to the conductive layer 2. Since this connection is made by the alloy layer 11 formed by the chemical reaction between the coating portion 9 covering the core portion 8 and the through-hole plating 7, a stable and reliable electrical connection (conductivity) is achieved. Can be secured. That is, it is possible to obtain the substrate 1 having heat dissipation characteristics and sufficient electrical conduction. In addition, since conductivity can be ensured through the core portion 8 in this way, it is not necessary to separately form through holes and through hole plating for electrical conduction in the laminated wiring board 3. For this reason, the space for forming such a through hole becomes unnecessary, and it can contribute to the high density of the component mounting in the board | substrate 1 currently calculated | required. Further, the core portion 8 is covered with the coating portion 9 on both sides of the through hole 6 in the penetrating direction. For this reason, it can prevent that the core part 8 will be exposed and can protect the core part 8. FIG. Moreover, both surfaces of the laminated wiring board 3 are covered with the cover plating layer 12 together with the coating portion 9 (metal piece 10). For this reason, the integration of the metal piece 10 and the laminated wiring board 3 is strengthened, and the metal piece 10 is reliably prevented from coming out of the through hole 6, and the integrity as the substrate 1 can be secured.

Further, by forming the core portion 8 and the coating portion 9 with different metals, the core portion 8 is formed with a metal having excellent electrical conduction and heat dissipation, and the coating portion 9 is formed with a metal that is easily alloyed. be able to. Thus, by using different metals for the core portion 8 and the coating portion 9, it is possible to select an optimum metal while taking into consideration the electrical continuity and heat dissipation action according to the characteristics of each other.

Here, as shown in FIG. 2, the coating portion 9 may be formed of a two-layer structure of an inner layer 13 that directly covers the core portion 9 and an outer layer 14 disposed outside the inner layer 13. Here, it is preferable that the core part 8, the inner layer 13, and the outer layer 14 are all formed of different metals. In particular, it is preferable that the core portion 8 is formed of copper, silver, or aluminum, the outer layer 14 is formed of tin or gold, and the inner layer 13 is formed of nickel. Thus, by forming the coating portion 9 with a two-layer structure (inner layer 13 and outer layer 14) made of different metals, the core portion 8 and the coating portion 9 can be prevented from being alloyed. That is, by forming the inner layer 13 with a metal having relatively low reactivity, the inner layer 13 is interposed between the core portion 8 and the outer layer 14, so that the core portion 8 and the outer layer 14 are alloyed. It is prevented. Furthermore, even if the inner wall surface of the through-hole plating 7 has an uneven shape, by using a soft metal as the outer layer 14 (or the coating portion 9 when the coating portion 9 is not a two-layer structure), the outer layer 14 (coating part 9) follows this uneven shape, so that the metal piece 10 can be reliably held in the through hole 6. Considering these, the core portion 8 is preferably made of any metal of copper, silver, or aluminum having high electrical conduction characteristics and heat dissipation characteristics. Further, the outer layer 14 is preferably made of any metal of tin or gold (or copper tin alloy) having high spreading characteristics. The inner layer 13 is preferably formed of nickel having low reactivity.

The substrate 1 described above can be manufactured by the substrate manufacturing method according to the present invention. This manufacturing method is represented in the flowchart shown in FIG. In this method, a laminated wiring board forming step is first performed (step S1). In this step, a laminated wiring board 3 as shown in FIG. 4 is obtained by stacking a plurality of insulating layers 4 and conductive layers 2 and pressing them in the laminating direction. The insulating layer 4 is made of, for example, an insulating resin material, and the conductive layer 2 is formed of a conductive material as a pattern. In order to form a laminated wiring board having four conductive layers 2, for example, a so-called single-sided board (a copper-clad laminate in which a copper foil is formed only on one side) in which the conductive layer 2 is formed only on one side of the insulating layer 4 is used. Two sheets are sandwiched between so-called double-sided plates (copper-clad laminates with copper foils formed on both sides) in which the conductive layer 2 is formed on both sides of the insulating layer 4 and laminated. The insulating layer 4 is made of, for example, a prepreg in which a sheet-like glass cloth 5 that is a cloth woven with glass fiber yarns is placed in an epoxy resin.

Next, a through-hole plating forming process is performed (step S2). In this step, first, a through hole 6 as shown in FIG. 5 penetrating the laminated wiring board 3 is formed. The through hole 6 is formed by drilling the laminated wiring board 3 with a drill, punch press, laser, or the like. The through hole 6 has a substantially cylindrical shape. In the plan view of the laminated wiring board 3 as viewed from above, the through hole 6 has a circular shape.

After the through hole 6 is formed, the through hole 6 is plated. Through this plating process, a through-hole plating 7 as shown in FIG. 6 is formed on the inner wall of the through-hole 6. Since the through hole plating 7 is formed in contact with the inner wall of the through hole 6, the conductive layer 2 communicating with the inner wall of the through hole 6 and the through hole plating 7 are electrically connected. For this reason, copper is preferable as the plating material. Since this plating process is performed on the entire surface of the laminated wiring board 3, the through-hole plating 7 deposited by the plating process is formed on both surfaces of the laminated wiring board 3 and the inner wall surface of the through-hole 6.

Next, a metal piece forming step is performed (step S3). You may perform this metal piece formation process before the laminated wiring board formation process and through-hole plating formation process which were mentioned above. In this step, first, the metal core portion 8 is formed. The core portion 8 has a substantially cylindrical shape. The core portion 8 is formed, for example, by machining a metal plate or bar. Specifically, it is formed by punching a metal plate into a substantially cylindrical shape, or appropriately cutting a long, substantially cylindrical rod material into a predetermined length. Further, since the core portion 8 plays a role of heat dissipation and conduction of the substrate 1, a metal having excellent heat dissipation and conduction characteristics is used for the core portion 8. Next, the core portion 8 is plated. A metal different from the core portion 8 is used for the plating process. A film portion 9 is formed on the entire surface of the core portion 8 plated in this manner. Thus, the metal piece 10 is formed by covering the entire surface of the core portion 8 with the coating portion 9.

Next, a pressing process is performed (step S4). In this step, first, the metal piece 10 is inserted into the through hole 6 as shown in FIG. Therefore, the diameter of the metal piece 10 is smaller than the diameter of the through hole 6 (specifically, the through hole plating 7). Then, in a state where the metal piece 10 is disposed in the through hole 6, the metal piece 10 is pressed from the vertical direction (on both sides of the through hole through direction). Thereby, as shown in FIG. 8, the diameter of the metal piece 10 is expanded outward. The film portion 9 comes into contact with the through-hole plating 7 by expanding the diameter of the metal piece 10. The pressing may be performed by placing a plate for pressing on one surface of the metal piece 10 and pressing the pressing member only from the other side.

Next, an alloy film forming step is performed (step S5). In this step, the metals forming the coating portion 9 and the through-hole plating 7 are alloyed to form an alloy film 11 as shown in FIG. Specifically, the contact portion between the film portion 9 and the through-hole plating 7 is heated and alloyed. This heating is naturally accelerated by heat treatment such as solder resist curing and reflow performed during the substrate manufacturing process. That is, the heat treatment not only means that the contact portion between the coating portion 9 and the through-hole plating 7 is heated, but also means the heat treatment for the entire laminated wiring board 3 including this contact portion. .

Next, a lid plating layer forming step is performed (step S6). In this step, the lid plating layer 12 is formed on both surfaces of the laminated wiring board 3. The lid plating layer 12 is formed to form the substrate 1 as shown in FIG. In the laminated wiring board 3, the film portions 9 of the metal pieces 10 are exposed on both surfaces that are both sides of the through hole 6 in the penetration direction. The lid plating layer 12 is formed by plating including the coating portion 9. That is, the lid plating layer 12 is formed by performing plating on both surfaces of the laminated wiring board 3. This alloying step is actually performed at the same time as or before the alloy film forming step.

Thus, according to the manufacturing method of the board | substrate 1 which concerns on this invention, since a metal-plating process is performed so that the whole surface may be covered with the film part 9 with respect to the core part 8 in a metal piece formation process, it is a subsequent press process. The core portion 8 can be protected when the metal piece 10 is pressed. That is, since the entire surface of the core portion 8 is covered with the coating portion 9, the surface pressed in the pressing step is not exposed. Thus, the reliable protection of the core part 8 is realizable by performing the metal piece formation process of covering the whole surface of the core part 8 which plays a role of heat dissipation and conduction. In addition, since the coating portion 9 different from the core portion 8 is formed in advance in the metal piece forming step, and this coating portion 9 and the through-hole plating 7 are alloyed in the alloy film forming step, this alloy is formed in the coating portion. 9 and the through-hole plating 7 become an alloy layer 11 formed by a chemical reaction. For this reason, stable and reliable electrical connection (conductivity) using the alloy layer 11 can be ensured. Such stable electrical continuity cannot be realized only when the same kind of metals (for example, copper) are in physical contact with each other. This is an effect obtained by bringing different metals into contact and alloying them. Since the alloy film 11 in which stable electrical connection is ensured in this way covers the core portion 8, as a result, the core portion 8 is joined to the through-hole plating 7 through the alloy film 11. Thereby, the electrical connection between the core part 8 and the conductive layer 2 is securable. That is, it is possible to obtain the substrate 1 having heat dissipation characteristics and sufficient electrical conduction.

Further, through the through-hole plating forming step, metal piece forming step, pressing step, and alloy film forming step, it is possible to ensure electrical continuity with the conductive layer 2 through the core portion 8, so that the laminated wiring board 3 is electrically connected separately. There is no need to form through holes for conduction and plated through holes. For this reason, the space for forming such a through hole becomes unnecessary, and it can contribute to the high density of the component mounting in the board | substrate currently calculated | required in recent years. In the lid plating layer forming step, both surfaces of the laminated wiring board 3 are covered with the lid plating layer 12 together with the coating portion 9 (metal piece 10). For this reason, the integration of the metal piece 10 and the laminated wiring board 3 is strengthened, and the metal piece 10 is reliably prevented from coming out of the through-hole 6 (through-hole plating 7), and the integrity as the substrate 1 is ensured. it can.

Here, in the metal piece forming step, the two-layered coating portion 9 composed of the inner layer 13 and the outer layer 14 may be formed by subjecting the core portion 8 to two-layer plating. In that case, it is preferable that the core part 8, the inner layer 13, and the outer layer 14 are all formed of different metals. In particular, the gold core portion 8 is preferably formed of copper, silver, or aluminum, the outer layer 14 is formed of tin or gold, and the inner layer 13 is preferably formed of nickel. Thus, the core part 8 and the film part 9 are formed of different metals in the metal piece forming step, so that the core part 8 is a metal having excellent electrical continuity and heat dissipation (for example, copper, silver, aluminum). The coating portion 9 can be formed of a metal (for example, tin, gold) that is easily alloyed. Thus, by using different metals for the core portion 8 and the coating portion 9, it is possible to select an optimum metal while taking into consideration the electrical continuity and heat dissipation action according to the characteristics of each other.

Furthermore, as described above, the core portion 8 and the coating portion are formed by performing two-layer plating in the metal piece forming step and forming the coating portion 9 as a two-layer structure (inner layer 13 and outer layer 14) made of different metals. 9 can be prevented from alloying. That is, by forming the inner layer 13 with a metal having relatively low reactivity, the inner layer 13 is interposed between the core portion 8 and the outer layer 14, so that the core portion 8 and the outer layer 14 are alloyed. It is prevented. Furthermore, even if the inner wall surface of the through-hole plating 7 has an uneven shape, by using a soft metal as the outer layer 14 (or the coating portion 9 when the coating portion 9 is not a two-layer structure), the outer layer 14 (coating part 9) follows this uneven shape, so that the metal piece 10 can be reliably held in the through hole 6. Considering these, the core portion 8 is preferably made of any metal of copper, silver, or aluminum having high electrical conduction characteristics and heat dissipation characteristics. Further, the outer layer 14 is preferably made of any metal of tin or gold (or copper tin alloy) having high spreading characteristics. The inner layer 13 is preferably formed of nickel having low reactivity.

1: substrate, 2: conductive layer, 3: laminated wiring board, 4: insulating layer, 5: glass cloth, 6: through hole, 7: through hole plating, 8: core portion, 9: coating portion, 10: metal piece , 11: alloy film, 12: lid plating layer, 13: inner layer, 14: outer layer

Claims

A laminated wiring board in which a plurality of conductive layers made of a conductive material are formed;
A through hole formed through the laminated wiring board;
Through-hole plating covering the inner wall of the through-hole and electrically connected to the conductive layer;
A metal piece that is arranged inside the through-hole plating, and that is made of a metal core part and a metal film part that covers the entire surface of the core part and is different from the core part;
A substrate comprising: an alloy film that is disposed between the coating portion and the through-hole plating, and is formed of the mutual metal forming the coating portion and the through-hole plating.
The coating part is composed of a two-layer structure of an inner layer directly covering the core part and an outer layer arranged outside the inner layer,
The substrate according to claim 1, wherein the core portion, the inner layer, and the outer layer are all made of different metals.
The core part is formed of copper, silver, or aluminum,
The outer layer is formed of tin or gold;
The substrate according to claim 2, wherein the inner layer is made of nickel.
A laminated wiring board forming step of forming a laminated wiring board by stacking a plurality of insulating layers made of an insulating resin material and a conductive layer formed of a conductive material as a pattern, respectively, and pressing in a laminating direction;
A through hole plating forming step of forming a through hole penetrating the laminated wiring board and forming a through hole plating electrically connected to the conductive layer on an inner wall of the through hole by performing a plating treatment;
A metal in which a metal core is formed, a coating is formed on the core by plating with a metal different from the core, and the entire surface of the core is covered with the coating A metal piece forming step of forming a piece;
With the metal piece inserted into the through hole and disposed in the through hole, the metal piece is expanded by pressing the metal piece, and the coating portion of the metal piece and the through hole plating A pressing step for contacting the
An alloy film forming step of forming an alloy film by alloying each other metal forming the film part and the through-hole plating by heating a contact portion between the film part and the through-hole plating. A method for manufacturing a substrate, comprising:
In the metal piece forming step, the coating portion having a two-layer structure composed of an inner layer and an outer layer is formed by performing a two-layer plating process on the core portion, and the core portion, the inner layer, and the outer layer are all formed. The method of manufacturing a substrate according to claim 4, wherein the substrate is made of a different metal.
The said metal piece formation process WHEREIN: The said core part is formed with copper, silver, or aluminum, the said outer layer is formed with tin or gold | metal | money, The said inner layer is formed with nickel, The said inner layer is formed. A method for manufacturing a substrate.