JP3272993B2 - Relay board, method of manufacturing the same, and method of connecting the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a BGA having a plurality of connection terminals (connection pads) on one principal plane (substrate surface).
A substrate such as a type integrated circuit board, provided with the same connecting terminals at positions corresponding to the connection terminals (mounting pads), the relay substrate is interposed between the mounting substrate such as a mother board for mounting the substrate, As a The present invention relates to a manufacturing method and a connection method thereof.

[0002]

2. Description of the Related Art Recent advances in integrated circuit (IC) technology have increased the number of input / output terminals provided on an IC chip.
Accordingly, input / output terminals formed on an IC mounting substrate on which an IC chip is mounted are increasing. However, when the input / output terminals are provided on the peripheral portion of the substrate, the size of the substrate is increased in accordance with the number of the terminals, and the cost and the yield of the IC mounting substrate are undesirably increased.

[0003] Therefore, a so-called PGA (pin grid array) type substrate in which pins are arranged in a grid or staggered pattern on the main surface (plane) of an IC mounting substrate is widely used. However, in order to further increase the number of terminals or reduce the size, there is a limit in a PGA type substrate in which pins are mounted on the substrate surface.

Therefore, the following method is used. That is, a pad (land) is used instead of a pin on the substrate surface.
Are formed in a grid or staggered pattern, and this pad has
A bump to which a terminal member made of a substantially spherical (ball-shaped) high-temperature solder or a metal having good solder wettability such as Cu or Ag is soldered in advance by eutectic soldering is provided. On the other hand, pads are formed on the printed circuit board (PCB) such as the motherboard of the other party at positions corresponding to the pads on the IC mounting board, and eutectic solder paste is applied to the pads. Thereafter, the two are superposed and heated to melt the solder paste, and the two are connected via a terminal member by soldering. Generally, a substrate provided with only pads in a lattice pattern is LG
An A (land grid array) type substrate and a substrate having a ball-shaped terminal member (connection terminal) on a pad are called a BGA (ball grid array) type substrate.

By the way, in this way, the IC mounting substrate,
Linear or lattice-like (including staggered) on the plane of the printed circuit board
When terminals such as pads and bumps are formed on the IC board and the IC mounting board is connected to the printed board, the thermal expansion coefficient differs depending on the material of the IC mounting board and the printed board.
A thermal expansion difference occurs in the plane direction. That is, when viewed from the terminal member, the connected IC mounting substrate and the printed circuit board tend to change their dimensions in opposite directions in the plane direction, so that a shear stress acts on the terminal member and the pad.

[0006] The shear stress is maximized between the two farthest terminals among the connected terminals. That is, for example, when the terminal group is formed in a lattice shape and the outermost terminal forms a square, the largest difference in thermal expansion between the two terminals located on the diagonal of the outermost periphery of the square is obtained. Occurs and the largest shear stress is applied.
In particular, when connecting an LGA type or BGA type substrate to a printed circuit board, the interval (pitch) between the terminals is relatively large, and therefore the distance between the farthest terminals is likely to be large. In particular, when a ceramic substrate is used for the LGA type or BGA type substrate, the shear stress generated is large because the thermal expansion coefficient is greatly different from that of a commonly used glass epoxy printed circuit board.

[0007] When such shear stress is applied, the solder together with the terminal member may come off from the pad. Also,
Due to repeated thermal stress, cracks almost parallel to the pad are made on the solder near the pad, leaving one thin skin of the solder along the pad surface, and may eventually break (break), resulting in high connection reliability. Could not get. Eutectic solder is often used as the solder near the pad, as described above, and is relatively hard and brittle, and tends to change with time due to heat or stress, so that cracks occur due to repeated stress.

[0008] This problem is particularly caused by a ceramic LGA type substrate (or BGA type substrate) having a relatively small coefficient of thermal expansion.
And a printed circuit board made of a resin such as glass epoxy having a relatively large coefficient of thermal expansion. In this case, cracks often occur in the eutectic solder near the pads on the ceramic substrate side. This is because ceramics are hard and cannot easily absorb stress, but resin printed circuit boards are relatively soft and pads made of Cu or the like formed on the resin printed board are also soft, so they absorb stress.

[0009]

On the other hand, the present inventors have disclosed in Japanese Patent Application Nos. 9-82033 and 9-82.
In No. 123, the connection between the board and the mounting board is facilitated by interposing the relay board between the board and the mounting board, and furthermore, the deformation of the protruding portion of the soft metal body inserted into the relay board main body, etc. It is proposed that the stress be relieved.

However, when the relay board is used, when connecting the board or the mounting board to the relay board in an overlapped manner, the relay board receives vibrations and shocks when handling or moving in a reflow furnace, and the relay board is connected to the relay board. In some cases, the board was connected to the board or the mounting board while being shifted. If both are connected in such a displaced manner, there is the danger that the connection strength between the relay board and the board or the mounting board will be reduced, and that the insulation distance between the terminals will be reduced and the insulation will be reduced. There is.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and facilitates mutual connection between a substrate and a mounting substrate, and is less likely to be displaced by vibration or impact at the time of connection. aims relay board that allows a reliable connection, the method of manufacturing their, and to provide a connection method.

[0012]

First, a solution according to the present invention is directed to a mounting method having a substrate having connection pads on one main plane and a mounting pad at a position corresponding to the connection pad on one main plane. A connection board for connecting the board to the mounting board by being interposed between the board and the connection pad on the first face side and connecting to the mounting pad on the second face side. A relay board body having a substantially plate shape having a first surface and a second surface and having a plurality of through holes penetrating between the first surface and the second surface; And at least one of a first protrusion protruding from the first surface and a second protrusion protruding from the second surface, and at least one of the first protrusion and the second protrusion. Yes and the soft metal body tip formed by the surface having a concave portion, a That is a relay board.

According to the present invention, the tip of the first or second projection is made flat or has a recess. In order to connect the relay board to the board or the mounting board, the first protruding portion and the connecting pad of the board or the tip of the second protruding portion and the mounting pad of the mounting board are arranged to abut via solder paste. Then, the solder paste is melted to connect the two. At this time, the problem that the tip of the protruding portion and the pad are connected with the lateral displacement caused by vibration or impact during handling or moving in the solder reflow furnace is less likely to occur, and the relay board and the board (or mounting Substrate) can be reliably connected.

Further, the soft metal body inserted into the relay board main body deforms the stress generated between the board and the mounting board or the board and the relay board, or the stress between the relay board and the mounting board, which is caused by a difference in thermal expansion coefficient or the like (for example, Plastic deformation). Therefore, without breaking the soft metal body,
Further, the connection pads of the board connected to the soft metal body, the mounting pads of the mounting board, or the solder or the soft metal body in the vicinity thereof are not broken or broken by the stress. In addition, since the stress applied to the relay board main body from the soft metal body is received from the direction perpendicular to the through hole wall surface of the relay board main body, the relay board main body itself is not easily broken.

Further, since the soft metal body has a protruding portion on at least one of the first surface side and the second surface side,
The stress generated between the board or the mounting board and the relay board can be absorbed more by the protrusion. This is because the protruding portion can be deformed without being restricted by the through hole of the relay board main body, so that more deformation is possible, and the protruding portion is easily deformed to release the stress. Further, since a part of the soft metal body inserted into the through hole of the relay board main body is used as the protruding portion, the vicinity of a portion of the soft metal body intersecting with the first or second surface of the relay board main body (that is, the protrusion) Since the stress applied to the base portion of the portion is reduced by the deformation of the soft metal, no crack or the like occurs.

Here, examples of the substrate include a wiring substrate such as an IC mounting substrate on which an IC chip and other electronic components are mounted. The connection pad is a terminal provided in a linear shape or a lattice shape (including a staggered shape) on one principal plane (substrate surface) of the substrate for electrical connection with the mounting substrate. Examples of a substrate having a bent substrate surface include:
An LGA substrate in which pads (lands) are arranged in a grid pattern is exemplified, but the pads need not necessarily be arranged in a grid pattern.

On the other hand, the mounting board is a board for mounting the board, and may be a printed board such as a motherboard. On this mounting substrate, mounting pads for electrical connection with the substrate are formed on one principal plane (substrate surface). Examples of the mounting board having the mounting pads include a printed board in which the pads are arranged in a grid pattern.However, the pads do not necessarily have to be arranged in a grid pattern. May be provided at a position corresponding to.

The relay board of the present invention is interposed between the board and the mounting board and connected to each other. For convenience, the side connected to the board is the first surface side, and the connecting board is connected to the mounting board. The two sides are distinguished from each other as the second surface side. Further, the material of the relay board body may be selected in consideration of the material and thermal expansion coefficient of the board to be connected and the mounting board, for example, alumina, mullite, aluminum nitride,
Ceramics such as glass ceramics are exemplified. Also, glass-epoxy resin, glass-polyimide resin,
A composite material such as a glass-BT resin or a composite material of a resin such as epoxy and ceramic powder can also be used. In addition, it is preferable that the material of the relay board main body be ceramic, since the strength of the relay board main body is high and the heat resistance is high, so that the relay board main body has high strength and does not deform even when repeatedly heated by rework or the like.

Further, the through-hole is usually constituted by a single hole, but also includes a group of a plurality of small through-holes (small through-hole group) provided close to each other. In this case, the soft metal inserted into each of the small through holes constitutes one soft metal body as a whole.

The soft metal body absorbs, by deformation, stress generated between the substrate and the mounting substrate, between the substrate and the relay substrate main body, or between the relay substrate main body and the mounting substrate due to a difference in thermal expansion coefficient or the like. It is made of soft metal. Specific materials include lead (Pb) and tin (S
n), zinc (Zn) and alloys containing these as main components, and Pb-Sn-based high-temperature solder (for example, Pb 90%
-Sn10% alloy, Pb95% -Sn5% alloy) and white metal. Since lead, soot and the like have a recrystallization temperature of room temperature, they recrystallize even if they undergo plastic deformation. Therefore, even if repeated stress is applied, it does not easily break (break), which is convenient. In addition, high purity copper (Cu) and silver (Ag) can be used because they are soft.

The connection between the relay board and the board or the mounting board, that is, the connection between the soft metal body and the connection pad or the mounting pad may be performed by using solder having a lower melting point than the soft metal body. When using such a solder, it is preferable to select such that there is an appropriate difference in the melting point of both, for example,
When a high-temperature solder of 90% Pb-10% Sn (melting point: 301 ° C.) is used as the soft metal body, 36% -Pb of Sn is used.
64% eutectic solder (melting point: 183 ° C) and its composition (Pb 20 to 50%, Sn 80 to 50%) Pb-
An Sn alloy or the like may be used. As other components, those to which an appropriate amount of In, Ag, Bi, Sb, or the like is added may be used. This solder may be attached to a connection pad or an attachment pad in advance, and may be a so-called solder bump.

The first soft metal member provided on the relay substrate
The protruding heights of the surface side and the second surface side may be appropriately selected according to the material of the relay board main body, the material of the board and the mounting board, and the like. When the relay board is interposed and connected between the board and the mounting board, the distance (distance) between the board and the relay board body and the distance between the mounting board and the relay board body can be made appropriate. It is. Therefore, the projecting height may be different between the first surface side and the second surface side. In general, the larger these distances, the more the stress can be absorbed. However, the distance between the board and the mounting board is usually limited. Therefore, it is preferable to increase the protruding height on the side where the difference in thermal expansion becomes large due to a difference in material or the like.

Here, the protruding height means a height from the surface of the relay board body to the tip of the soft metal body protruding,
The protruding height is zero when the surface and the soft metal body are flush with each other or when the surface is recessed from the surface. That is, the first protrusion height (Z1) indicates a height from the first surface of the relay board main body to the tip of the soft metal body protruding toward the first surface, and the second protrusion height (Z2) indicates the relay height. It refers to the height from the second surface of the substrate body to the tip of the soft metal body protruding toward the second surface.

[0024] Further, the solution means of the present invention is characterized in that
A substrate having connection pads on a main plane;
Mounting base having mounting pads at positions corresponding to connection pads
And a connection pad on the first surface side.
And by connecting to the mounting pad on the second surface side
A relay board for connecting the board and the mounting board.
Thus, it has a substantially plate shape having a first surface and a second surface.
Having a plurality of through holes penetrating between the first surface and the second surface
Inserted into the spliced board body and the through hole Above
A first protrusion protruding from the first surface and a protrusion protruding from the second surface
And at least one of the second protrusions,
At least one of the first protrusion and the second protrusion
The tip of the
The substrate and the relay substrate of the first surface side and the second surface side
Thermal expansion difference with the board body, the mounting board and the relay board
Compared with the thermal expansion difference with the body, the side with the larger thermal expansion difference
The protruding height of lead, tin, zinc and
A soft metal body made of an alloy mainly composed of
It is a connecting board.

According to a third aspect of the present invention, there is provided the relay board according to the first or second aspect, wherein the soft metal body has a melting point higher than that of the soft metal body on the first surface side. A relay layer having a solder layer made of low solder, and having a second protruding portion whose tip is a flat surface or a surface having a concave portion.

According to the present invention, since the solder layer is provided on the first surface side, connection with the connection pads on the substrate can be easily performed. Moreover, at the time of this connection, only the solder is melted, and the soft metal body is not melted, so that the board and the relay board can be connected. Further, since the relay board of the present invention has the second projecting portion, when the relay board and the mounting board are connected, thermal stress or the like generated between the relay board and the mounting board due to a difference in thermal expansion coefficient or the like. Can be absorbed by the soft metal body. In addition, since the tip of the second protrusion is a flat surface or a surface having a concave portion, when connecting the relay board and the mounting board, there is a problem that the second protrusion and the mounting pad are displaced and connected. It is hard to occur, and the relay board and the mounting board can be securely connected.

Moreover, solutions of claim 4, a relay board according to claim 1 or claim 2, the first protrusion or the said tip is on a surface having a flat surface or recess (2) A relay board, wherein the projecting portion has a columnar shape having a projecting height larger than its diameter.

According to the present invention, the protruding portion having a flat end or the like has a column shape whose protruding height is larger than its diameter. When the stress due to the difference in the coefficient of thermal expansion between the board and the mounting board is large, if the relay board is mounted sideways, that is, the tip of the protrusion and the pad of the board or the mounting board are not correctly connected. If the connection is made laterally displaced, stress concentrates on the connection portion and cracks are easily generated. On the other hand, according to the present invention, the tip of the protruding portion can be made flat or the like to prevent lateral displacement. Further, since the columnar protruding portion has a protruding height larger than its diameter, it can be easily bent (deflected). Deformation), thereby absorbing the stress.

According to a fifth aspect of the present invention, there is provided the method for manufacturing a relay board according to the second aspect , wherein the first protrusion of the soft metal body inserted into the through hole of the relay board body. A method of manufacturing a relay board, comprising a step of removing a top portion of a portion or a second protruding portion to flatten a tip.

According to the present invention, the coplanarity of the tip of each projection can be reduced because the top of the first or second projection formed once is removed to make the surface flat. Therefore, the connectivity with the board and the mounting board can be improved. Note that the coplanarity refers to the minimum value of the distance between the two planes when the tip of each projection is located in two planes parallel to each other, and indicates the quality of the connectivity of the projections. It is an indicator.

Here, the method of removing the top of the protrusion is as follows.
The material may be selected in consideration of the material and the like of the soft metal body, and examples thereof include lap polishing and surface grinding.

A sixth aspect of the present invention is the method for manufacturing a relay board according to the first or second aspect , wherein the soft metal body is inserted into a through hole of the relay board body. And pressing the top of the first or second projecting portion to make the tip a flat surface or a surface having a recess.

According to the present invention, if the top of the protruding portion is pressed to be a flat surface, the coplanarity of each end is improved, and the connectivity with the board or the mounting board can be improved. Further, since a flat surface or a surface having a concave portion is formed by pressing, even a soft metal such as a high-temperature solder, which is difficult to process, can be easily processed.

Further, a solution according to a seventh aspect is the method for manufacturing a relay board according to the first or second aspect , wherein the relay board is made of a material that does not wet the molten soft metal. A molten soft metal receiving jig having a concave portion at each of the above positions, and a bottom surface of the concave portion each having a flat surface or a surface having a convex portion was prepared, and was melted in the concave portion so as to rise from the upper end surface of the concave portion. A step of filling the soft metal, and a step of stacking the relay substrate body on the molten soft metal receiving jig so that the through-hole overlaps the concave portion and the molten soft metal enters the through-hole,
A step of contacting the bottom surface of the concave portion and cooling while holding at least in the concave portion and the through hole to solidify the soft metal.

According to the present invention, the soft metal receiving jig having the concave portion and the bottom surface of which is a flat surface or a convex portion is used to fill the concave portion with the molten soft metal and make contact with the bottom surface. Cool and solidify. Therefore, the tip of the protruding portion can be made a flat surface or a surface having a concave portion only by melting and softening the soft metal without going through a process such as polishing.

[0036] Furthermore, a solution according to claim 8 is a contractor.
A method for manufacturing a relay board according to claim 1 or 2.
Is the material resistant to heat and not wettable by molten soft metal?
Corresponding to the through holes of the relay board body, respectively.
Prepare a solder piece holding jig with a recess at the position, and
Put the first ball made of the above soft metal into the recess
At the same time, a second button made of the soft metal is provided at an end of the recess.
Mounting the relay board body, and
Positioning so that the second ball fits into the through hole
And the second ball of the relay substrate body
From the side opposite to the high-temperature
Relay the flat surface of a load jig made of a material that does not get wet
Place it on the board by pressing it against the board
Jig side And melt the first hole and the second ball.
And a soft metal body is inserted into the through hole of the relay board body.
A step of penetrating; a first protrusion or a second protrusion of the soft metal body.
2 Work to make the tip of the protruding part a flat surface or a surface with a concave part
And a method of manufacturing a relay board comprising:

Further, a solution according to claim 9 is one of
A substrate having connection pads on a plane;
Mounting board having mounting pads at positions corresponding to connection pads
And the connection pad is connected to the connection pad on the first surface side.
And connected to the mounting pad on the second surface side.
The relay board for connecting the board and the mounting board
Connected to the board and / or the mounting board
A connection method of the relay board, wherein the first surface and the second surface
And has a substantially plate shape having
A relay substrate body having a plurality of through holes through which the
The first projecting through the holes and projecting from the first surface
Of the protrusions and the second protrusions protruding from the second surface,
At least one of the first projection and the second projection.
At least one end of the protrusion is flat or concave
And a soft metal body formed on a surface having a portion.
The tip of the soft metal body of the relay board has a flat surface.
Or the first protrusion formed on the surface having the concave portion or
The second protruding portion is connected to the substrate with solder paste via a solder paste.
To the connection pad or the mounting pad on the mounting board.
Of the relay board to melt the solder paste
The connection method.

[0038]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. Embodiment 1 FIG. 1 is a partially enlarged cross-sectional view of a relay board 10 according to the present embodiment. That is, the relay board 10 is made of alumina ceramic containing alumina as a main component (90%), has a thickness of 0.3 mm, has a square plate shape of 25 mm on a side, and has a first surface 1a and a second surface 1b. It has a relay board main body 1 having a plurality of through holes H (inner diameter 0.8 mm) penetrating therethrough. The through holes H are formed in a grid pattern at a pitch of 1.27 mm, each of which has 19 holes (361 in total). Also,
High-temperature solder (including first and second protrusions 6a and 6b that are inserted through the through-hole H and project from both surfaces thereof, and a tip (lower end in the figure) of the second protrusion 6b is a flat surface 6s). Pb
90% -Sn10%).
Further, eutectic solder (Pb3) is provided on the first protrusion 6a.
7% -Sn 63%) (having a height of 0.08
mm).

Note that a tungsten base metal layer 2 (about 10 μm in thickness) and an electroless Ni—B plating layer 3 ( The thickness is about 2 μm), and the soft metal body 6 is welded to the Ni-B plating layer 3. Here, the first
The protrusion height (first protrusion height) Z1 of the protrusion 6a from the first surface 1a is 0.012 mm, and the protrusion height (second protrusion height) of the second protrusion 6b from the second surface 1b. Z2 is 1.4
5 mm. That is, the projecting heights Z1 and Z2 are different from each other. Furthermore, the projecting height is Z1 <Z.
It is 2. In addition, the second projection 6b, which has a substantially columnar shape,
Has a diameter of 0.88 mm.

Next, the relay board 10 is connected to the board and the mounting board, for example, as follows. First, as a substrate to be connected to the relay substrate 10, a substantially square LG having a thickness of 1.0 mm and a side of 25 mm as shown in FIG.
An A-type substrate 20 was prepared. The LGA type substrate 20 is made of the same alumina ceramic as that of the relay substrate main body 1, has a flip chip pad 21 for mounting an IC chip by flip chip connection on an upper surface 20 a in the figure, and has an external connection on a lower surface 20 b in the figure. A connection pad 22 is provided as a terminal. This connection pad 22 has a diameter of 0.86 mm,
In order to match the position of the soft metal body 6 of the relay board 10,
It is arranged in a grid shape with a pitch of 1.27 mm, 19 pieces each in the vertical and horizontal directions,
Electroless Ni-B plating is applied on the underlying molybdenum layer, and further thin electroless gold plating is applied to prevent oxidation. The flip chip pads 21 and the connection pads 22 are connected to each other by internal wiring (not shown).

A printed board 40 as shown in FIG. 2B was prepared as a mounting board. Printed circuit board 40
Is a substantially square plate with a thickness of 1.6 mm and a side of 30 mm.
It is made of a glass-epoxy resin composite material (JIS: FR-4), and the main surface 40 a is provided with mounting pads 22 at positions corresponding to the connection pads 22 of the LGA type substrate 20 and, therefore, the soft metal body 6 of the relay substrate 10. 42 are formed.
The mounting pads 42 are made of copper having a thickness of 25 μm, and have a diameter of 0.72 mm, a pitch of 1.27 mm, and a total of 361 in a grid pattern, each having 19 pieces in length and width.

First, the relay substrate 10 and the LGA type substrate 20 are stacked and passed through a reflow furnace at a maximum temperature of 220 ° C. to melt the solder layer 7 made of eutectic solder, and connect them. As shown in (1), a connection body 60 is formed. In the connection body 60, the distance A1 between the lower surface 20b of the substrate 20 and the first surface 1a of the relay substrate body 1 was 0.10 mm. On the other hand, the projecting height Z2 of the second projecting portion 6b projecting downward from the relay board main body 1 (second surface 1b) in the figure is 1.45 m.
m.

Thereafter, a low-melting solder paste (eutectic solder paste) S of about 250 μm
The connection between the printed circuit board 40 and the connector 60 applied to a thickness of 5 mm is connected. That is, the second protruding portion 6 b is abutted so as to be aligned with the mounting pad 42, and the connecting body 60 is placed on the printed circuit board 40. Thereafter, by passing through a reflow furnace having a maximum temperature of 220 ° C. and heating, the low-melting solder paste S on the mounting pad 42 is melted to form a solder layer 8, and as shown in FIG. A structure 50 connecting the relay board 10 and the printed board 40 was formed. In this structure 50, the lower surface 20b of the substrate 20
A1 between the first board 1 and the first surface 1a of the relay board body 1 is 0.10
mm, while the distance A2 between the second surface 1b of the relay substrate main body 1 and the upper surface 40a of the printed circuit board 40 is 1.48 mm.
It became. In this example, the solder layers 7 and 8
Although an example in which the same eutectic solder is used for (low-melting solder paste S) is shown, for example, by using a solder having a high melting point for the solder layer 7, when the solder layer 8 is formed, the solder layer 7 is melted. For example, the melting point of the solder layer 7 may be higher than the melting point of the solder layer 8.

By the way, the tip of the second protruding portion 6b does not usually become flat, and when the soft metal is melted and penetrated, it usually becomes substantially hemispherical due to the surface tension of the melted soft metal. . As shown in FIG. 4B, the second protrusion 6
Let us consider a case where the tip 6s' of b is hemispherical. Then, at the time of connection between the printed circuit board 40 and the connection body 60, that is,
When the printed circuit board 40 and the relay board 10 are connected to each other via the solder paste S and then subjected to vibration or shock during handling or moving in a reflow furnace, the mounting pad 42 and the soft metal There is a possibility that the position of the body 6 with respect to the second projecting portion 6b is shifted (laterally shifted).
If both are connected with such displacement, it is considered that problems such as a decrease in the connection strength between the relay board and the mounting board and a decrease in the insulation distance due to a short insulation distance between the terminals may occur. Can be

On the other hand, in the relay board 10 of the present embodiment, the tip of the second protrusion 6b is a flat surface 6s substantially perpendicular to the axis of the soft metal body 6. Therefore, even if the above-mentioned vibration or impact is received, the mounting pad 42 and the second protruding portion 6 of the soft metal body 6 as shown in FIG.
The position of b does not shift. Paste S and second
This is because the tip of the protruding portion 6b is in close contact with the protruding portion 6b, and the resistance to lateral displacement increases. In the present embodiment, the case where the tip of the second protruding portion 6b is a flat surface has been described, but it may be a surface in which a concave portion is partially formed. Similarly, the resistance to the lateral displacement can be increased.

Further, in the structure 50 of this embodiment, almost no stress is generated between the board 20 and the relay board main body 1. This is because the board 20 and the relay board main body 1 are made of the same material, and there is no difference in thermal expansion. On the other hand, stress occurs between the relay board main body 1 and the printed board 40. This is because the relay board main body 1 and the printed board 40 are made of different materials. In this case, the maximum stress occurs in the second protruding portion 6b of the soft metal body 6 on the printed board 40 side and in the solder layer 8 near the printed board 40. However, since the soft metal body 6 (the second protrusion 6b) is easily plastically deformed, the soft metal body 6 is deformed at the second protrusion 6b to reduce the stress. Therefore, the stress generated between the relay board main body 1 and the printed board 40 is reduced as a result, and a reliable connection that is not easily broken can be obtained.

In particular, no stress is applied by the relay substrate 10 to the solder layer 7 near the connection pad 22 on the side of the substrate 20 which has conventionally been easily broken. On the other hand, the stress between the relay board 10 and the printed board 40 is deformed and absorbed by the soft metal body 6, so that the second protrusion 6 b of the soft metal body 6 is hardly broken, and the mounting pad of the printed board 40 Also, the solder layer 8 of 42 is hardly broken.

The relay board body 1 and the printed board 40
Can be increased. This is because the protrusion height Z2 of the second protrusion 6b is increased. By doing so, the stress generated between the relay board main body 1 and the printed board 40 can be reduced by the increase in the distance A2. The second protruding portion 6b has a diameter (0.88 m
m), the second protrusion height Z2 (1.45 mm) is a columnar shape that is larger than that of m), so that the shape itself can be easily bent, and the stress can be absorbed here as well.
Furthermore, the second protrusion 6b made of a soft metal body can absorb stress even if it is plastically deformed.

In a normal case, the distance between adjacent soft metal bodies (the distance between connection pads) is set to a predetermined value, so that the maximum diameter of the protrusion is limited by this distance.
On the other hand, it is considered that the height of the protrusion is often large in the allowable range. If the protrusion is columnar, it is possible to form a protrusion that is as high as possible within the limit of the maximum diameter of the protrusion, so the distance between the board or mounting board and the relay board body is larger, and the protrusion is relatively large. , So that more stress can be relaxed. Therefore, it is possible to improve the connection reliability between the board and the relay board or between the relay board and the mounting board in which such a substantially columnar protrusion is interposed, and to prolong the life of the connection section.

Further, in the present embodiment, the second projecting portion 6b
Has a flat surface 6s, so that a displacement between the relay board 10 and the printed circuit board 40 where stress occurs can be prevented. Therefore, the second protruding portion 6b and the printed circuit board 4
The mounting pad 42 is connected to the mounting pad 42 without any displacement, and cracks are less likely to occur at the connecting portion due to stress. Therefore,
By making the protruding portion columnar, stress can be further relieved, and furthermore, by making its tip a flat surface (or a surface having a concave portion), it prevents side displacement and connects at the correct position.
Since cracks due to stress concentration due to displacement are also prevented, a more reliable connection can be achieved.

In the above-described example, the relay board 10 is once attached to the LGA type board 20 to form a connecting body (substrate with a relay board) 60 between the board and the relay board, and further connected to the printed board 40. However, it is also possible to adopt a method of manufacturing all at once. That is, the printed board 40, the relay board 10, and the LGA type board 20 are stacked in this order, reflowed, and the board 20, the relay board 10, and the relay board 1 are reflowed.
0 and the printed circuit board 40 may be connected (soldered) at once. Further, the relay board 10 and the printed board 40 may be connected first. In any case, if the relay board 10 of this example is used, it is not necessary to place the terminal members one by one on the connection pads and the mounting pads, and the board is connected to the board by one or two times of heating (reflow). The mounting board can be connected via the relay board. Therefore,
For IC chip manufacturers and users, cumbersome processes and equipment can be omitted.

Next, a method of manufacturing the relay board 10 will be described. First, an alumina ceramic green sheet G having a through hole H is prepared by a known ceramic green sheet forming technique. As shown in FIG. 5A, a tungsten paste P is applied to the inner peripheral surface of the through hole H of the sheet G and the peripheral edge H1 of the through hole.

Next, this sheet G is fired in a reducing atmosphere at a maximum temperature of about 1550 ° C. to form a ceramic relay board main body 1 and a base metal layer 2 mainly composed of tungsten as shown in FIG. Form. The fired relay board body (hereinafter, also referred to as the body) 1 has a thickness of 0.3 mm, has a substantially square plate shape with a side of 25 mm, and penetrates between the first surface 1a and the second surface 1b. The inner diameter of the hole H is φ0.8mm
In a grid pattern at a pitch of 1.27 mm, each of the 19
A total of 361 (= 19 × 19) through holes are formed. The thickness of the base metal layer 2 is about 10 μm.

Further, on this underlying metal layer 2, FIG.
As shown in FIG. 1, an electroless Ni-B plating layer 3 having a thickness of about 2 μm is formed, and a metal layer 4 for welding a soft metal is formed on both sides as described later. Furthermore, in order to prevent oxidation of the Ni-B plating layer 3, a thickness of 0.1 μm is formed on the Ni-B plating layer 3.
An electroless gold plating layer (not shown) is formed.

Next, the soft metal body 6 is inserted into the through hole H. In this embodiment, the columnar soft metal body 6 is formed using the molten soft metal receiving jig N. That is, as shown in FIG. 6 (a), on the upper surface of a solder piece holding jig N made of carbon, which is heat-resistant and does not wet the molten high-temperature solder, at positions corresponding to the through holes H, respectively. 0.9m in diameter
m, a depth of 1.95 mm, and a concave portion N1 having a conical tip. A small diameter (φ) that penetrates downward through the holding jig N is provided at the top (the lowest part in the figure) of the concave portion N1 of the holding jig N.
(0.2 mm).

First, a high-temperature solder (Pb 90% -Sn 10% solder) ball D1 having a diameter of 0.8 mm is put into each concave portion N1 of the holding jig N. In this example, two pieces were put into each recess. Next, the end (upper end) of the concave portion N1
1.0mm diameter high-temperature solder (Pb90% -Sn10
% Solder) The ball D2 is placed. At this time, the concave portion N1
It is preferable that the distance between the ball D1 and the ball D2, which have already been put into the tank, does not come into contact with each other, and that the ball D1 and the ball D2 come into contact with each other when the high-temperature solder is melted, as described later. In this case, the ball D2 comes into close contact with the upper end edge of the concave portion N1 and does not move (or hardly moves), so that the positioning when the relay board main body 1 described later is mounted becomes easy.

Thereafter, as shown in FIG.
The relay board main body 1 is placed on the upper side in FIG. At this time,
The positioning is performed so that the ball D2 fits into the through hole H.
Further, from above the relay board main body 1, that is, from the side opposite to the side where the ball D2 is located, a plane (a lower surface in the figure) of a load jig Q made of stainless steel, which is heat-resistant and does not wet molten high-temperature solder. Q1 is pressed against the upper surface of the main body 1 and compressed downward.

Next, under a nitrogen atmosphere, a maximum temperature of 360
These are charged into a reflow furnace at a temperature of 1 ° C. and a maximum temperature holding time of 1 minute to melt the high-temperature solder balls D1 and D2. Then, the molten high-temperature solder D2 is inserted into the through hole H of the main body 1 pushed down in the figure by the load jig Q and welded to the metal layer 4 on the inner periphery of the through hole H. On the other hand, at the upper end portion of the through hole H, the load jig Q follows the plane Q1 and becomes flat. The high-temperature solder D2 is also injected into the concave portion N1 of the holding jig N. Then, it comes into contact with the molten high-temperature solder D1, and the two tend to unite due to surface tension. However, since the solder D2 is welded to the metal layer 4 and is integrated with the main body 1, the solder D2 cannot separate from the main body 1 and fall down, so that the high-temperature solder D1 is pulled up against the gravity. Integrate. The main body 1 is pushed down by the load jig Q until it is pressed against the upper surface N3 of the holding jig N.

The gas vent hole N2 serves to release air trapped in the recess N1 when melting the high-temperature solder balls D1 and D2. However, receiving jig N
Does not get wet with the solder and the gas vent hole N2 has a small diameter,
The solder does not enter the gas vent hole N2.

Thereafter, when the high-temperature solder is solidified by cooling, as shown in FIG. 7, on the lower side of the relay board main body 1 in the figure, the side surface follows the shape of the side wall of the concave portion N1. A relay substrate 10 having a substantially hemispherical second protruding portion 6b at the top and a soft metal body 6 having a shape that hardly protrudes was formed on the upper side.

Since the gold plating layer on the Ni—B plating layer 3 is diffused and disappears in the molten high-temperature solder, the high-temperature solder and the Ni—B plating layer 3 are directly welded to each other to form a soft layer made of high-temperature solder. The metal body 6 is fixed to the relay board main body 1.

Next, as shown in FIG.
The top (bottom end in the figure) of b was removed by lap polishing, and the tip was made a flat surface 6 s substantially perpendicular to the axis of the soft metal body 6. Thereby, in this example, the diameter (maximum diameter) of the cross section is 0.88 mm, and the protrusion height Z2 of the second protrusion 6b is 1.4.
5 mm, and became a substantially columnar shape having a height higher than the diameter (maximum diameter) up to the top. On the other hand, on the upper surface side in the drawing, the first protrusion height Z1 from the upper surface was 0.012 mm. In addition, since the flat surfaces 6s at the tips of the second projections 6b are all located on substantially the same plane by polishing, the coplanarity at the tips of the second projections 6b can be reduced.

Next, as shown in FIG.
0.4mm diameter low melting point solder ball (Pb-
A Sn eutectic solder ball) Ey is placed. In order to mount the ball Ey, the ball Ey is set so that the through hole RH of the ball regulating plate R is positioned above the soft metal body, and the ball Ey is scattered and rocked on the regulating plate R, and the ball Ey is shaken. According to the method of dropping the ball Ey into the hole RH, the ball Ey can be easily placed. In this example, the thickness of the regulating plate R is 0.5 mm and the through hole RH
Has a diameter of 0.6 mm. In this example, FIG.
As shown in (1), a soft metal body holding jig U having a concave portion U1 into which the tip of the second protrusion 6b is fitted is used, and the tip of the second protrusion 6b is fitted into the recess U1 of the jig U. It is convenient to perform it in the state. This is because the soft metal body 6 is formed of a high-temperature solder that is soft and easily deformed.

Thereafter, under nitrogen atmosphere, the maximum temperature 22
These are charged into a reflow furnace at 0 ° C. and a maximum temperature holding time of 1 minute to melt the low melting point solder balls Ey. The soft metal body 6 does not melt under this temperature condition. The melted low melting point solder wets and spreads on the upper surface of the soft metal body 6 in the figure to become a solder layer 7 (see FIG. 1). This solder layer 7
Since the volume of the low-melting solder ball Ey is regulated to be constant, the volume becomes constant and the height becomes uniform.
In the present embodiment, the solder layer 7
Was 0.08 mm to the top (uppermost end in the figure).

In this way, as shown in FIG. 1, the relay board main body 1 having the through hole H penetrating between the first and second surfaces 1a and 1b in the drawing, and being inserted through the through hole H. The relay board 10 having the soft metal body 6 having the second protruding portions 6b protruding from the lower surface in the figure was formed. Also, this relay board 1
0 on the soft metal body 6 on the first surface 1a side.
A solder layer 7 having a lower melting point is formed.
In the present embodiment, the second protruding portion 6b has a cylindrical shape, but may have a tapered shape or a prismatic shape. However, when the flat surface at the tip is widened, lateral displacement is less likely to occur. Further, in the present embodiment, an example has been shown in which the flat surface 6s is provided by polishing for all the second protrusions 6b of the soft metal body 6, but it is not always necessary that all the protrusions have a flat surface. Not
It may be processed by polishing or the like so that only some of the protrusions have a flat surface. In this case, the lateral displacement of the relay board is prevented by the protrusion having the flat surface.

(Embodiment 2) Next, Embodiment 2 will be described. The relay board 210 of the present embodiment has substantially the same shape as the relay board 10 of the above-described first embodiment, and the manufacturing method is different only in the processing of the tip of the second protruding portion. Only the different parts will be described. That is, the first embodiment
7, after the soft metal body 6 was inserted into the relay board main body 1 as shown in FIG. 7, the top of the second protrusion 6b was removed by polishing to obtain a tip 6s having a flat surface. On the other hand, in the present embodiment, the top is processed by pressing. That is, as shown in FIG. 10A, a predetermined depth is formed at a position corresponding to the second projecting portion 6b, the bottom surface is flat, and both bottom surfaces are formed to belong to a common plane (same plane). A press jig V (made of stainless steel) having a concave portion V1 is prepared, and the concave portion V1 of the press jig V is prepared.
The second protruding portions 6b are respectively inserted into the inside.

Then, when pressed in the vertical direction in the figure, the soft metal body 6 made of high-temperature solder is easily deformed and follows the shape of the concave portion V1. Therefore, the relay board 2 of the present embodiment
In FIG. 10, as shown in FIG.
Of the second protrusion 206b has a flat surface 206s following the bottom surface of the concave portion V1, and has a second protrusion height of 1.5 mm.
Becomes After that, in the same manner as in the first embodiment, the first
A solder layer is formed on the surface side or connected to a board or a mounting board. In the present embodiment, the flat surface 206s can be easily formed simply by pressing. Further, the flat surfaces 206s can be made to belong to substantially the same plane, so that good coplanarity can be obtained. Furthermore, no polishing debris or the like is generated by polishing, and a step of cleaning and removing abrasive grains is unnecessary.

In the above example, the press jig V having the concave portion V1 is used. However, the concave portion V1 is not formed, and the tip is made to be a flat surface even when compressed by a flat surface press jig. Can also. In this case, the flat surface at the tip of the second protrusion 206b is formed following the flat surface of the press jig, so that the coplanarity at each tip is good. However, since the second protrusion 6b is inserted into the recess V1, there is an advantage in the case where the recess V1 is formed in that the lateral displacement hardly occurs and the second protrusion can be prevented from being bent and deformed.

Further, as shown in FIG. 10 (c), a pressing jig V 'having a concave portion V1' having a convex portion V2 'formed on the bottom surface.
May be used. In this case, by the same compression as described above, as shown in FIG. 10D, a relay board 210 'having a surface having a concave portion at the tip 206s' can be formed. Even in this case, as in the first embodiment, when connecting the relay board 210 ′ and the mounting board 40, after the two are overlapped, vibration or impact may occur during handling or when moving in a reflow furnace. When received, the position of the mounting pad 42 and the second protruding portion 206b 'of the soft metal body 206' do not shift. This is because the paste and the tip of the second protruding portion 6b come into close contact with each other and hold the paste in the concave portion, so that the resistance to lateral displacement increases.

Third Embodiment Next, a third embodiment will be described. The relay board 310 of the present embodiment also has substantially the same shape as the relay board 10 of the above-described first embodiment, and the manufacturing method is the same except that only the portion for inserting the soft metal into the through hole is different. Portions are omitted, and only different portions will be described. That is, in the first embodiment, as shown in FIGS. 6 and 7, a molten soft metal receiving jig N having a concave portion N1 having a conical lower end is used, and high-temperature solder balls D1, D2 are used.
Was melted, and the soft metal body 6 was inserted into the relay board main body 1, and then the top of the second projecting portion 6b was removed by polishing to obtain a tip 6s having a flat surface.

On the other hand, in the present embodiment, a molten soft metal receiving jig M having a concave portion M1 in which the bottom surface M2 is a flat surface and both bottom surfaces belong to a common plane is used. The recess M1 is filled with the molten soft metal F by filling it, and the soft metal is solidified to form a second projection having a flat end. That is, as shown in FIG. 11A, it is formed at a position corresponding to the second protruding portion 6b, and the bottom surface M
2 is a flattened molten metal receiving jig M (made of carbon) having a flattened recess M1 having a diameter of 0.9 mm and a depth of 1.9 mm.
Are prepared, and the concave portion M of the molten soft metal receiving jig M is prepared.
The molten high-temperature solder (Pb 90% -Sn 10% solder) F is injected into each one. At this time, the injected molten high-temperature solder F is filled in the concave portion M1 and further slightly (about 0.6 mm in this example) than the upper surface M3 of the jig M.
Inject so that it rises to the height of the.

Next, as shown in FIG. 11B, the same relay board main body 1 as that manufactured in the first embodiment is used.
Is positioned from above the jig M such that each through hole H corresponds to the concave portion M1, and is pressed from above using the weighting jig Q used in the first embodiment. As a result, the molten high-temperature solder F is welded to the metal layer 4 and penetrates into the through hole H to be filled. This is because the molten high-temperature solder F was injected so as to rise from the upper end surface of the concave portion M1, that is, the jig upper surface M3. Thereafter, when the molten high-temperature solder F is cooled while contacting the bottom surface M2 of the concave portion M1 to solidify the high-temperature solder, the soft metal body 306 is inserted into the through-hole H as shown in FIG. 2 protrusion 30
Reference numeral 6b denotes a column having a second protrusion height Z2 'of 1.9 mm in accordance with the shape of the concave portion M1, and the tip 306s thereof becomes a flat surface following the bottom surface M2 of the concave portion M1. According to the present embodiment,
In order to make the tip a flat surface, post-processing such as polishing and pressing is not required as compared with the above two embodiments.

In this embodiment, the bottom surface M of the concave portion M1
2 shows an example in which a flat jig M is used.
As shown in FIGS. 3 (a) and 3 (b), the bottom surfaces M2 ′ and M2 ″ may have a convex shape.
When the jigs M ′ and M ″ having 2 ′ and M2 ″ are used, the tip of the second protrusion becomes a surface having a concave portion.

In the above-described three embodiments, the second protruding portion of the soft metal body has a columnar shape, and its tip is a flat surface or a surface having a concave portion. Obviously, the first protrusions may be connected by abutting. Further, it is needless to say that the present invention is not limited to the above embodiment, and can be appropriately modified and applied within the scope of the present invention.

[Brief description of the drawings]

FIG. 1 is a partially enlarged cross-sectional view of a relay board according to a first embodiment.

FIG. 2 is a cross-sectional view of a board connected to a relay board and a mounting board.

FIG. 3 is a cross-sectional view showing a state in which the relay board, the board, and the mounting board are connected.

FIG. 4 is an explanatory diagram illustrating the relationship between the shape of the tip of a second protruding portion and lateral displacement.

FIG. 5 is an explanatory diagram illustrating a process of manufacturing a relay substrate main body in a process of manufacturing the relay substrate.

FIG. 6 is an explanatory diagram illustrating a step of inserting a high-temperature solder ball into a through hole in a process of manufacturing the relay board.

FIG. 7 is an explanatory diagram illustrating a state in which a soft metal body is inserted into a through hole in a process of manufacturing the relay board.

FIG. 8 is a partially enlarged cross-sectional view of the relay board.

FIG. 9 is an explanatory view illustrating a step of further forming a solder layer on the first surface side of the relay board.

FIG. 10 is an explanatory diagram illustrating a press step of the relay board according to the second embodiment.

FIG. 11 is an explanatory diagram illustrating a step of inserting a molten soft metal body in a step of manufacturing the relay board according to the third embodiment.

FIG. 12 is a partially enlarged cross-sectional view of a relay board according to a third embodiment.

FIG. 13 is an explanatory diagram showing an example of the shape of another jig according to the third embodiment.

[Explanation of symbols]

 10, 210, 310 Relay board 1 Relay board main body 2 Base metal layer 3 Plating layer 4 Metal layer 6, 206, 306 Soft metal body 6a First protrusion 6b, 206b, 306b Second protrusion 6s, 206s, 306s Tip 7 Solder layer H Through-hole 20 Board 22 Connection pad 40 Mounting board 42 Mounting pad

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01R 12/06 H01L 23/12 H05K 1/14 H05K 1/18 H05K 3/40

Claims (9)

(57) [Claims] 1. A connection board having a connection pad on one main plane and a mounting board having a mounting pad at a position corresponding to the connection pad on the one main plane, and the connection on the first surface side. A relay board for connecting the mounting board to the mounting board by connecting to the pad and connecting to the mounting pad on the second face side, wherein the relay board has a substantially plate shape having a first face and a second face. None, a relay board main body having a plurality of through holes penetrating between the first surface and the second surface; a first protruding portion inserted into the through hole and protruding from the first surface; comprising at least one of the second protruding portion protruding from the second surface, and a soft metal body comprising at least one of the distal end of the first protrusion and the second protrusion is a surface having a concave portion, A relay board having: 2. A connection between a substrate having a connection pad on one principal plane and a mounting board having a mounting pad at a position corresponding to the connection pad on the one principal plane, and the connection on the first surface side. A relay board for connecting the mounting board to the mounting board by connecting to the pad and connecting to the mounting pad on the second face side, wherein the relay board has a substantially plate shape having a first face and a second face. None, a relay board main body having a plurality of through holes penetrating between the first surface and the second surface; a first protruding portion inserted into the through hole and protruding from the first surface; comprising at least one of the second protruding portion protruding from the second surface, and Ri least one of the distal end of the first protrusion and the second protrusion name is on a surface having a flat surface or recess, the The first side and
Of the second surface side, the thermal expansion between the substrate and the relay substrate body
Tension difference, thermal expansion difference between the mounting board and the relay board body
The protrusion height on the side where the difference in thermal expansion is larger
And lead, tin, zinc and these mainly
Relay substrate having a soft metal bodies ing alloy. 3. The relay board according to claim 1, wherein the soft metal body has a solder layer made of solder having a lower melting point than the soft metal body on the first surface side. And a second protruding portion having a flat surface or a surface having a concave portion at the front end. 4. The relay board according to claim 1, wherein the first protrusion or the second protrusion whose tip is a flat surface or a surface having a concave portion is larger than a diameter thereof. A relay board having a columnar shape having a protruding height. 5. The method for manufacturing a relay board according to claim 2, wherein the top of the first protrusion or the second protrusion of the soft metal body inserted into the through hole of the relay board body is removed. A method for manufacturing a relay board, comprising: 6. The method for manufacturing a relay board according to claim 1, wherein the first protrusion or the second protrusion of the soft metal body inserted into the through hole of the relay board body. A method of manufacturing a relay board, which comprises a step of pressing the top of the substrate to make the tip a flat surface or a surface having a concave portion. 7. The method for manufacturing a relay board according to claim 1, wherein the relay board is made of a material that does not wet the molten soft metal, and has a concave portion at a position corresponding to the through hole. A step of preparing a molten soft metal receiving jig in which the bottom surface of the concave portion is a flat surface or a surface having a convex portion, and filling the molten soft metal in the concave portion so as to rise from the upper end surface of the concave portion; Stacking the relay board main body on the molten soft metal receiving jig so that the through hole overlaps and the molten soft metal enters the through hole; and bringing the molten soft metal into contact with the bottom surface of the concave portion, and at least A step of cooling while holding in the recesses and the through holes to solidify the soft metal. 8. The method for manufacturing a relay board according to claim 1, wherein the relay board is made of a material having heat resistance and not wettable by a molten soft metal, and corresponds to a through hole of the relay board body. A solder piece holding jig having a concave portion formed at a position is prepared, a first ball made of the soft metal is put into the concave portion, and a second ball made of the soft metal is placed at an end of the concave portion. And mounting the relay board body, and inserting the second through the through hole.
Positioning the ball so that it fits, and, from the side of the relay substrate body opposite to the side where the second ball is located, the plane of a load jig made of a material that is heat-resistant and does not wet the molten high-temperature solder. It is placed so as to be pressed against the relay board main body and is compressed toward the solder piece holding jig side to melt the first hole and the second ball, so that a soft metal body penetrates into the through hole of the relay board main body. A method of manufacturing a relay board, comprising: a step of inserting; and a step of making the tip of the first protrusion or the second protrusion of the soft metal body a flat surface or a surface having a recess. 9. A connection between a substrate having connection pads on one main plane and a mounting substrate having mounting pads at positions corresponding to the connection pads on one main plane, and the connection on the first surface side. A relay board for connecting the board to the mounting board by connecting to the pad and connecting the board to the mounting board on the second surface side by connecting the relay board to at least one of the board and the mounting board; A method, comprising: a relay board main body having a substantially plate shape having a first surface and a second surface, having a plurality of through holes penetrating between the first surface and the second surface; And a first protrusion protruding from the first surface and a second protrusion protruding from the second surface.
A soft metal body comprising at least one of the protruding portions, and a tip having at least one of the first protruding portion and the second protruding portion being a flat surface or a surface having a concave portion. Connecting the first or second protruding portion, the tip of which is a flat surface or a surface having a concave portion, to a connection pad of the substrate or a mounting substrate via a solder paste. A method of connecting a relay board that is arranged so as to abut against a pad and melts the solder paste.