JPH11126954A - Relay board and method of manufacturing the same - Google Patents

Abstract

(57) [Summary] [Object] To prevent breakage of a solder layer due to stress generated due to a difference in thermal expansion between an LGA type substrate and a printed circuit board, and to enhance reliability of electrical connection between the two boards. A column-shaped second-surface connection terminal made of high-temperature solder is fixed to a second-surface-side recessed portion of a relay substrate body, and the second-surface connection terminal is printed by a low-melting-point solder layer. It is soldered to the surface connection mounting pad 32 on the substrate 30. Via 12 is provided inside relay board body 9.
The via 12d is connected to the base 13b via the second surface connection pad 14c and to the first surface connection pad 14d on the first surface 9b.
The first surface side connection pad 14d is soldered to the surface connection pad 22 of the LGA type substrate 20 and the low melting point solder layer 10d. Then, the second surface side connection terminal 13 is plastically deformed by the stress, and the stress is relieved by the plastic deformation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a relay board for electrically connecting a substrate provided with surface connection pads and a substrate provided with surface connection mounting pads, and a method of manufacturing the same. The present invention is suitable as a relay substrate that is interposed between a mounted ceramic substrate and a resin printed substrate and electrically connects the two substrates, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, BGA (ball grid array) type substrates and LG
A (land grid array) type substrate is known. FIG. 13 is a partial sectional explanatory view showing a BGA type substrate connected to a printed circuit board. On the lower surface of the IC chip mounting substrate 70, surface connection pads (lands) 71 are formed in a lattice or staggered shape. On the lower surface of each surface connection pad 71, a ball-shaped terminal 73 is eutectic. Soldered by solder 72. Surface connection mounting pads 74 are formed on the upper surface of the printed board 75 at positions corresponding to the terminals 73, and each surface connection mounting pad 74 is soldered to the ball-shaped terminal 73 by the eutectic solder 72. I have. That is, the IC chip mounting board 70 in a state where the terminals 73 are soldered to the respective surface connection pads 71 on the lower surface.
Constitute a BGA type substrate. The surface connection pad 71
Are formed of W (tungsten), and the surface connection attachment pad 74 is formed of Cu (copper). The terminal 73 is formed of a metal having good wettability, such as high-temperature solder, Cu, or Ag.

[0003]

The IC chip mounting board 70 and the printed board 75 have different thermal expansion coefficients due to different materials. Thereby, for example, IC
As shown in FIG. 13, a force that changes in a direction indicated by an arrow F3 acts on the printed board 75 by heat generated from a power supply unit of a computer having the chip mounted board 70 and the printed board 75. , A force that changes in the direction indicated by the arrow F4 acts. In other words, when viewed from the ball-shaped terminal 73, the connected IC chip mounting board 70 and the printed board 75 tend to change their dimensions in the directions opposite to each other in the plane direction.
3. A shear stress acts on a connection portion between the surface connection pad 71 and the surface connection mounting pad 74.

[0004] Therefore, the soldered portion 76 is broken by the above shear stress, and the eutectic solder 72 is detached from the surface connection pad 71.
0 and the printed circuit board 75 have a problem of poor electrical connection. The above-mentioned shear stress is maximum between two terminals 73 farthest among the terminals 73 to be surface-connected. For example, when the terminals 73 are formed in a lattice shape and the outermost terminal 73 forms a square, the two terminals 7 located on the diagonal of the outermost periphery of the square are used.
The largest thermal expansion difference occurs among the three, and the largest shear stress is applied.

In particular, when the IC chip mounting board 70 is made of ceramics and the printed board 75 is made of resin such as glass epoxy, the thermal expansion coefficient of the printed board 75 (thermal expansion coefficient α = 15 to 20 × 10 ^-6 ) is much larger than the thermal expansion coefficient of the IC chip mounting substrate 70 (α = 8 × 10 ^-6 ), so that the difference in thermal expansion between the two substrates becomes large.
Therefore, the above-mentioned shear stress becomes large, so that the above-mentioned electrical connection failure easily occurs. In this case, cracks often occur in the eutectic solder near the surface connection pads on the ceramic IC chip mounting substrate side. This is because ceramics are hard and cannot easily absorb stress, but resin printed circuit boards are relatively soft, and mounting pads made of Cu or the like formed on the resin printed board are also soft, so that they absorb stress. Even when the IC chip mounting substrate and the printed circuit board are formed of a resin having the same coefficient of thermal expansion, even if the entire substrate is compared by the copper wiring and the like formed inside the IC chip mounting substrate,
There is a difference in the coefficient of thermal expansion between the chip mounting board and the printed board. In addition, the resin-made IC chip mounting substrate is soft and easily deformed as compared with the case of the ceramic IC chip mounting substrate, and thus is easily affected by the thermal expansion of the mounted IC chip. As a result, even when the IC chip mounting substrate and the printed circuit board are formed of the same resin, the part of the resin IC chip mounting substrate, especially immediately below the IC chip mounted, has a thermal expansion coefficient of the printed circuit board. May be different.
As described above, even when the resin-made printed circuit board is connected to the resin-made IC chip-mounted board, the connection between the IC chip-mounted board and the printed board is affected by the internal wiring and the mounted IC chip. In some cases, a thermal expansion difference occurs between the two, and as a result, problems such as poor connection between the two may occur. Although it is conceivable to increase the adhesion strength between the IC chip mounting board 70 and the printed board 75, the eutectic solder 7 near the surface connection pad 71 may be caused by repeated thermal stress.
2 is fatigued by metal and cracks occur, and eventually the eutectic solder 72 is broken, resulting in poor electrical connection. That is,
In the above-mentioned conventional BGA type substrate and the like, there is a problem that reliability of electrical connection between the IC chip mounting substrate 70 and the printed substrate 75 is low.

Accordingly, the present invention provides a first substrate (IC chip mounting substrate 70) having a substrate surface on which surface connection pads (pads 71) are provided, and a substrate having a substrate surface on which surface connection mounting pads are provided. A second substrate (printed circuit board 7) having a thermal expansion coefficient different from that of the first substrate
5) An object of the present invention is to realize a relay board and a method for manufacturing the same, which can increase the reliability of electrical connection with the relay board.

[0007]

In order to achieve the above object, according to the first aspect of the present invention, a first substrate having a substrate surface provided with surface connection pads and a surface connection mounting pad are provided. Electrically connected between the surface connection pad and the surface connection mounting pad between the second substrate and the second substrate having a substrate surface having a thermal expansion coefficient different from the thermal expansion coefficient of the first substrate. A relay substrate having a substantially plate shape having a first surface and a second surface, and a relay substrate body made of an electrically insulating material, and formed on the second surface side toward the first surface side. The second surface-side concave portion is fixed to the bottom surface and the inner peripheral surface of the second surface-side concave portion, and has a front end portion protruding from the second surface. A second surface side connection terminal electrically connected to the relay substrate; It is formed inside the body, to adopt technical means of having a via for electrically connecting the surface contact pad and the second-surface-side connecting terminal.

According to the invention described in claim 2, in the relay board according to claim 1, the inner peripheral surface of the second surface side recess is
Technical means of being formed in a tapered shape is adopted.

According to a third aspect of the present invention, in the relay board according to the first aspect, the inner peripheral surface of the second surface side recess is
A technical means of being formed in a step shape is adopted.

According to a fourth aspect of the present invention, in the relay board according to any one of the first to third aspects,
A second surface side connection pad formed on the bottom surface of the second surface side recess, for electrically connecting the second surface side connection terminal and the via, and formed on the first surface side; Technical means of having a first surface side connection pad for electrically connecting the via and the surface connection pad is adopted.

According to a fifth aspect of the present invention, in the relay board according to any one of the first to fourth aspects,
A technical means is adopted in which the protruding portion of the second surface side connection terminal is formed in a column shape having a protruding height larger than the maximum diameter of the protruding portion.

According to a sixth aspect of the present invention, in the relay board according to any one of the first to fifth aspects,
The second surface side connection terminal employs a technical means that is formed of a soft metal.

According to a seventh aspect of the present invention, in the relay board according to any one of the fourth to sixth aspects,
A low melting point metal layer is formed on the upper surface of the first surface side connection pad and the tip of the second surface side connection terminal by a metal having a melting point lower than the melting point of the second surface side second surface side connection terminal. The technical means that have been adopted.

According to the invention described in claim 8, in the relay board according to any one of claims 1 to 7,
The relay board main body employs a technical means that has substantially the same thermal expansion coefficient as the first board.

According to a ninth aspect of the present invention, in the relay board according to any one of the first to eighth aspects,
Technical means is adopted in which the first substrate is made of a ceramic material, and the relay substrate main body is made of the same ceramic material as the first substrate.

According to a tenth aspect of the present invention, in the relay board according to any one of the first to ninth aspects, the diameter of the via is smaller than the diameter of the recess on the second surface side. Employ strategic means.

According to an eleventh aspect of the present invention, there is provided the method for manufacturing a relay board according to any one of the first to tenth aspects, wherein the first ceramic green sheet has the first ceramic green sheet.
Forming a through hole, and forming a second through hole in a portion corresponding to the first through hole of a second ceramic green sheet to be laminated with the first ceramic green sheet; A via forming step of forming the via in the second through hole of the second ceramic green sheet, a metallizing layer forming step of forming a metallized layer in the first through hole, and the via forming step The second ceramic green sheet and the first ceramic green sheet having undergone the through-hole forming step correspond to the via and the first through-hole, and one end of the first through-hole is the first ceramic green sheet. A laminating step of laminating in a state where the second surface side concave portion is formed by being closed by the ceramic green sheet, and the first and second ceramic greens having passed through the laminating step. A firing step of firing and integrating the sheet to form the relay board main body, and a second surface side for forming the second surface side connection terminals inside the second surface side recess of the relay board main body after the firing step And a connection terminal forming step.

[0018] According to the invention described in claim 12, in the invention described in claim 11,
3. The method of manufacturing a relay board according to claim 1, further comprising a connection pad forming step of forming the first surface side connection pads and the second surface side connection pads on the second ceramic green sheet having undergone the via formation step. Adopt means.

According to the invention of claim 13, according to claim 11,
Alternatively, in the method for manufacturing a relay board according to claim 12, the second surface side connection terminal forming step has a shape corresponding to a shape of a protruding portion of the second surface side connection terminal, and is formed on a molten metal. A metal material for using a jig having a concave portion having an inner surface that is not wet at a position corresponding to the second surface side concave portion, and storing a metal material for forming the second surface side connection terminal in the concave portion of the jig. An accommodating step, and a jig arranging step of arranging the jig after the metal material accommodating step in a state in which the concave portion is located below the second surface side concave portion of the relay substrate body formed in the firing step. The metal material accommodated in each concave portion of the jig after the jig disposing step is melted, cooled and solidified while holding the molten metal in the concave portion and the second surface side concave portion. The second
And a molding step of molding the surface-side connection terminals.

According to the fourteenth aspect, in the eleventh aspect,
Alternatively, in the method of manufacturing a relay board according to claim 12, the second surface side connection terminal forming step has a diameter corresponding to a diameter of a protruding portion of the second surface side connection terminal, and is formed on a molten metal. Jigs each having a through hole having an inner surface that is not wetted at a position corresponding to the second surface side concave portion,
A jig arranging step of arranging the through hole above the second surface-side concave portion of the relay board main body with the opening side of the second surface-side concave portion facing upward formed by the firing step; A metal material accommodating step of accommodating a metal material for forming the second surface side connection terminal in the through hole of the jig having passed through the jig disposing step; A molding method in which the metal material accommodated in the through-hole is melted, cooled and solidified while holding the molten metal in the through-hole and the second-surface-side recess to form the second-surface-side connection terminal. And a technical means of having a process.

[0021] According to the invention described in claim 15, according to claim 11 of the present invention.
15. The method for manufacturing a relay board according to claim 14, wherein the upper surface of the first surface connection pad and the tip of the second surface connection terminal after the second surface connection terminal forming step. In addition, a technical means of having a low melting point metal layer forming step of forming a low melting point metal layer with a metal having a melting point lower than the melting point of the second surface side connection terminal is adopted.

[0022]

According to the present invention, when the two substrates are dimensionally changed in the opposite directions with respect to the plane due to the difference between the thermal expansion coefficients of the first and second substrates, stress is generated at the connection portion between the first and second substrates and the relay substrate. I do. However, claim 1 to claim 1
By using the relay substrate described in 5, the above stress can be reduced as follows. The relay board main body is made of an electrically insulating material, and has a second surface side recess formed on the second surface side toward the first surface side. The second-surface-side concave portion has a second-surface-side connection terminal fixed to the bottom surface and the inner peripheral surface of the second-surface-side concave portion, and is formed such that a distal end portion protrudes from the second surface. This second side connection terminal is
It is electrically connected to the surface connection attachment pad of the second substrate.
Further, vias are formed inside the relay substrate main body to electrically connect the second surface side connection terminals and the surface connection pads of the first substrate. That is, the relay board and the surface connection mounting pad of the second board are electrically connected by the second surface side connection terminal projecting from the second surface of the relay board body, and the surface connection between the relay board and the first board is performed. The pads are electrically connected to the pads by vias formed inside the relay board main body.

Therefore, assuming that the connecting portion between the second surface side connection terminal and the surface connection mounting pad is a fulcrum, the force of the first and second substrates to change their dimensions in the directions opposite to each other in the plane direction is as described above. The rotation moment is converted into a rotational moment for rotating the relay substrate body about the fulcrum.
Then, the protruding portion of the second surface side connection terminal is deformed by the generated rotational moment (for example, plastic deformation).
However, the stress is alleviated by this deformation. Also, the second
Since the surface-side connection terminals are fixed to the bottom surface and the inner peripheral surface of the second surface-side concave portion, the stress acts in a direction perpendicular to the fixed inner peripheral surface. Hard to destroy. Further, since the second surface side connection terminal is fixed to the bottom surface and the inner peripheral surface of the second surface side concave portion, for example, the second surface side connection terminal is fixed to the flat surface portion of the second surface. The fixed part is difficult to peel off. As mentioned above,
According to the relay board according to claims 1 to 15,
Since the stress generated due to the difference in thermal expansion between the first and second substrates can be reduced, the occurrence of poor electrical connection between the first and second substrates can be reduced.

In particular, as in the second aspect of the present invention, it is preferable that the inner peripheral surface of the second surface side recess is formed in a tapered shape. That is, the stress acts on the contact portion between the second-surface-side connection terminal and the inner peripheral surface of the second-surface-side concave portion, but the shape of the inner peripheral surface of the second-surface-side concave portion is linear (columnar). In some cases, stress tends to concentrate on a portion (corner (see P1 and P2 in FIG. 7)) where the protruding tip of the connection terminal and the edge of the recess are in contact. However, by forming the inner peripheral surface in a tapered shape, stress can be dispersed to a portion where the connection terminal and the inner peripheral surface are in contact (tapered surface (see P3 in FIG. 14)). Can be prevented and durability can be increased.

Further, by forming the inner peripheral surface of the second-surface-side concave portion in a step-like manner as in the third aspect of the present invention, the plurality of corners at which the connection terminal and the inner peripheral surface come into contact with each other are formed. (See P4 and P5 in FIG. 15), it is possible to increase the durability of the relay board main body as compared with the one concentrated on one corner.

Further, the portion of the second surface side connection terminal projecting from the second surface is formed in a columnar shape in which the projecting portion is larger than the maximum diameter of the projecting portion. Preferably, it is formed. That is, when the protruding portion is, for example, spherical or hemispherical, if the protruding height is increased in order to increase the distance between the first and second substrates, the maximum diameter of the protruding portion is simultaneously increased. Therefore, the distance (pitch) between adjacent connection terminals is limited. However, as described above, when the shape of the protruding portion is columnar, the protruding height can be increased without changing the diameter, so that the above-described restriction can be eliminated. Further, even when the number of connection terminals increases, the above-described limitation can be prevented by reducing the diameter.
In general, the higher the protruding height of the second surface side connection terminal, the more the stress can be absorbed. However, the distance between the relay board and the resin printed board is usually limited.
Therefore, it is preferable that the protruding height of the second surface side connection terminal is set according to the magnitude of the thermal expansion difference between the second substrate and the relay substrate main body. That is, the larger the difference in thermal expansion between the relay board main body and the second board, the greater the stress generated between them. Therefore, the second surface side connection terminal for electrically connecting the relay board body and the second board to each other. By setting the protruding height in accordance with the magnitude of the thermal expansion difference, the magnitude of the rotational moment can be changed, so that the stress corresponding to the magnitude of the stress can be relaxed. It is.

Further, the second surface side connection terminal may be configured as follows.
It is preferable to be formed of a soft metal as in the invention described in (1). In other words, the above stress is applied to the deformation of the connection terminal,
For example, it can be absorbed by plastic deformation. Here, the soft metal is a soft metal that absorbs the above-mentioned stress by deformation, for example, lead (Pb), tin (S
n) and zinc (Zn), alloys containing these as main components,
And a Pb-Sn high-temperature solder (for example, Pb9
0% -Sn10% alloy, Pb95% -Sn5% alloy, etc.), white metal, high purity copper (Cu), silver (A
g).

Further, according to the second aspect of the present invention, the second
The second surface connection terminal is formed on the bottom surface of the surface side recess, and has the second surface side connection pad for electrically connecting the second surface side connection terminal and the via. Even in the case of a material that is difficult to adhere to the second surface side, the second surface side connection pad and the via can be electrically connected by the second surface side connection pad. For example, when the second-surface-side connection terminal is made of high-temperature solder and the bottom surface of the second-surface-side recess is made of alumina ceramic, the alumina ceramic has poor wettability with respect to the molten high-temperature solder. By forming a tungsten second surface side connection pad on the bottom surface of the substrate, the wettability is improved, so that the second surface side connection terminal and the via can be electrically connected. Further, the first surface is formed on the first surface side and electrically connects the via and the surface connection pad.
Since the surface-side connection pad is provided, even if the material for electrically connecting the via and the surface connection pad is hard to adhere to the via, the material and the via are electrically connected by the first surface-side connection pad. Can be connected.

According to a twelfth aspect of the present invention, the first surface side connection pad and the second surface side connection pad are formed on the second ceramic green sheet having been subjected to the via forming step. It can be formed by a connection pad forming step of forming a side connection pad.

According to the present invention, the upper surface of the first surface side connection pad and the tip of the second surface side connection terminal each have a lower melting point than the melting point of the second surface side connection terminal. It is preferable that the low melting point metal layer is formed of a metal having the following formula: That is, since the low-melting-point metal layer is formed at the connection portion between the surface connection pad and the surface connection mounting pad, for example, when connecting the relay substrate in a manufacturer that manufactures the first substrate or the second substrate However, there is no need to provide a facility for applying a low melting point metal (for example, low melting point solder paste) to the tips of the first surface side connection pads and the second surface side connection terminals.

The low-melting-point metal layer is provided on the upper surface of the first-side connection pad and the tip of the second-side connection terminal after the second-surface-side connection terminal forming step. Are formed by a low-melting-point metal layer forming step of forming a low-melting-point metal layer with a metal having a melting point lower than the melting point of the second surface side connection terminal.

Further, as in the invention according to claim 8,
It is preferable that the relay substrate body has substantially the same thermal expansion coefficient as the first substrate. That is, since there is almost no difference in thermal expansion between the first substrate and the relay substrate body, almost no stress is generated. On the other hand, since the interval between the relay board main body and the second board is made relatively large by the second surface side connection terminal, the stress between the relay board main body and the second board is reduced.

In particular, it is preferable that the first substrate is made of a ceramic material and the relay substrate body is made of substantially the same ceramic material as the first substrate. That is, since the ceramics have high strength and heat resistance, they do not deform even when repeatedly heated by rework.

Further, as in the invention according to claim 10,
It is preferable that the diameter of the via is smaller than the diameter of the concave portion on the second surface side. In other words, for example, a ceramic green sheet having a through hole formed thereon is placed on a stainless steel sheet as described in an embodiment of the invention described below, and paste-like tungsten is filled in the through hole. Then, the sheet is peeled off and formed by sintering the tungsten powder when the ceramic green sheet is fired. If the diameter of the through hole (diameter of the via) is large, when the sheet is peeled off, the filled tungsten paste is used. May stick to the sheet or fall off, making it difficult to fill.

Next, the relay board according to any one of the first to tenth aspects is manufactured by the manufacturing method according to the eleventh aspect. First, in the through-hole forming step,
A first through-hole is formed in the first ceramic green sheet, and a second through-hole is formed in a portion corresponding to the first through-hole of a second ceramic green sheet to be laminated with the first ceramic green sheet. I do. Next, in the via forming step, a via is formed inside the second through hole of the second ceramic green sheet, and in the metallizing layer forming step, a metallized layer is formed in the first through hole. That is, a metallized layer is formed in the first through-hole in order to fix the second-surface-side connection terminal in the first through-hole (the second-surface-side recess) in a subsequent second-surface-side connection terminal forming step. I do.

Next, in the laminating step, the second ceramic green sheet having undergone the via forming step and the first ceramic green sheet having undergone the through-hole forming step are connected with the via and the first ceramic green sheet.
The first through-holes are stacked so that one end of each of the first through-holes is closed by the second ceramic green sheet to form the second surface side recess. That is, the second
In order to electrically connect the second surface side connection terminal fixed in the second surface side concave portion and the via formed in the second through hole in the surface side connection terminal forming step, the first and second connection terminals are formed. The first and second ceramic green sheets are laminated so as to correspond to the through holes. Further, in order to form a second-surface-side recess for forming the second-surface-side connection terminal in a second-surface-side connection-terminal forming step, one end of the first through hole is formed by a second ceramic green sheet. The layers are stacked in a state where the second surface side concave portion is formed by being closed.

Next, in the firing step, the first
And the second ceramic green sheet is fired and integrated to form a relay substrate main body. In the second surface side connection terminal forming step, the second surface side connection is formed inside the second surface side recess of the relay substrate main body after the firing step. Form terminals. That is, the laminated first and second ceramic green sheets are fired to form a ceramic relay substrate body, and the second surface side recess is formed in the second surface side recess formed in the relay substrate body. Form connection terminals.

In particular, the second-surface-side connection terminal forming step includes:
It can be manufactured by the invention of claim 13.
First, in the metal material accommodating step, the second surface side connection terminal has a concave portion having a shape corresponding to the shape of the protruding portion of the second surface side connection terminal and having an inner surface which is not wet with the molten metal at a position corresponding to the second surface side concave portion. Using a jig, insert the second
A metal material for forming the surface side connection terminal is accommodated. That is, a jig for forming the second surface side connection terminal is prepared, and a metal material serving as a raw material for forming the second surface side connection terminal is accommodated in the recess of the jig.

Next, in the jig disposing step, the jig in which the metal material is accommodated in the concave portion is disposed so that the concave portion is located below the concave portion on the second surface side of the relay substrate body formed in the firing step. I do. In other words, the jig is arranged so that its concave portion corresponds to the concave portion on the second surface side of the relay substrate main body, and
Prepare to form surface-side connection terminals. Next, in the forming step, the metal material contained in each concave portion of the jig that has undergone the jig disposing step is melted, and the molten metal is cooled while being held in the concave portion and the second surface side concave portion. Then, the second surface side connection terminal is formed by solidification. That is, the molten metal in the concave portion is maintained at a state of reaching the bottom surface of the second surface side concave portion, and in this state, the molten metal is cooled and solidified, thereby being fixed to the bottom surface and the inner peripheral surface of the second surface side concave portion. Accordingly, the second-surface-side connection terminal having a tip portion protruding from the second surface of the relay board main body can be formed.

Further, the method according to claim 14 can be used instead of the step of forming the second surface side connection terminal according to claim 13. First, in the jig arranging step according to the thirteenth aspect, the jig is arranged such that its concave portion is located below the concave portion on the second surface side of the relay board main body. In the jig arranging step, the jig having a through hole having a diameter corresponding to the diameter of the protruding portion of the second surface side connection terminal is placed in a state where the opening side of the second surface side concave portion faces upward. Is arranged in a state where the through hole is located above the second surface side concave portion. In other words, the jig is arranged in a state where the through-hole is located above the second surface side recess of the relay substrate main body in a state where the opening side of the second surface side recess is facing upward, and the metal is placed in the metal material accommodating step later. Prepare to accommodate the material in the through-hole.

In the metal material accommodating step, a metal material for forming the second surface side connection terminal is accommodated in the through hole of the jig after the jig disposing step, and in the forming step, the metal material accommodating step is performed. The metal material accommodated in the through hole of the jig is melted, cooled while being held in the through hole and the recess on the second surface side, and solidified to form the second surface side connection terminal. .

[0042]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a relay board and a method of manufacturing the same according to the present invention will be described below with reference to FIGS. FIGS. 1A to 1D are cross-sectional explanatory views showing each step of the method for manufacturing a relay board according to the first embodiment. FIG. 2A is an explanatory view showing a method of filling a conductive metal for forming a via in the second through hole of the second ceramic green sheet, and FIGS. First
FIG. 4 is an explanatory view showing a method of forming a metallized layer on the inner peripheral surface of the first through hole of the ceramic green sheet. FIG.
FIG. 4 is a process diagram showing a manufacturing process of the method for manufacturing a relay board according to the first embodiment.

First, a first embodiment of the method for manufacturing a relay board according to the present invention will be described. First, a first ceramic green sheet 11 and a second ceramic green sheet 12 are formed by using a known ceramic green sheet forming technique, and FIG.
As shown in (1), a first through hole 11a is formed in the first ceramic green sheet 11 and a second through hole 12a is formed in the second ceramic green sheet 12 (step 10 in FIG. 9). The second through-hole 12a has a diameter smaller than the diameter of the first through-hole 11a, and when the second ceramic green sheet 12 is laminated on the upper surface of the first ceramic green sheet 11, the first through-hole 12a It is formed at a position included in the upper opening surface of the hole 11a.

Next, the second ceramic green sheet 1
The second second through-hole 12a is filled with a conductive metal forming a via. This filling is performed, for example, by the method shown in FIG. First, the second ceramic green sheet 12 is placed on the stainless steel sheet 18 placed on the table 19b. The sheet 18 has a through-hole 18a formed at a position corresponding to the second through-hole 12a. The second ceramic green sheet 12 is placed so that the second through-hole 12a and the through-hole 18a coincide with each other. Can be On the lower surface of the sheet 18, a hard paste-like conductive metal 12b for forming a via is applied in a mat shape.

Then, the upper surface of the second ceramic green sheet 12 is pressed by the load plate 19a in the direction indicated by F1 in the figure. Then, the conductive metal 12
b flows into the inside of the second through-hole 12a of the second ceramic green sheet 12 through the through-hole 18a of the sheet 18, and as shown in FIG. The conductive metal 12b is filled (step 12). In addition,
The conductive metal 12b can be filled in the second through hole 12a by screen printing. By the way, in the first embodiment, alumina ceramic is used as a material for forming the first and second ceramic green sheets 11 and 12. As the conductive metal 12b, a paste obtained by mixing a solvent or a resin with a conductive metal powder such as tungsten (W) or molybdenum (Mo) is used.

On the other hand, the first ceramic green sheet 1
In order to fix the base portion 13b of the second surface side connection terminal 13 in a step shown in FIG. 1D later, a metal made of tungsten as a metallization layer of the present invention is provided on the inner surface of the first through hole 11a. Form a layer. As shown in FIG. 2B, the tungsten paste 17 is evacuated into a first through-hole 11a formed in the first ceramic green sheet 11 in a direction indicated by an arrow F2 in the drawing, so that the tungsten paste 17 is removed. The inner peripheral surface 11d of the first through hole 11a is applied to the inner peripheral surface 11d of the first through hole 11a, as shown in FIG.
A tungsten layer 17a is formed on d (step 14). At this time, the first through hole 11a is moved from the edge of the lower opening surface to the first through hole 11a.
The protruding portion 17c of the tungsten layer is formed over the lower surface of the ceramic green sheet 11 of FIG.
As shown in (D), the protruding portion 17c may be removed by polishing.

Next, the second surface side connection pads 14a made of tungsten are formed on the lower surface of each conductive metal 12b, and the first surface side connection pads 14b made of tungsten are formed on the upper surface by screen printing (step 16). Next, FIG.
As shown in FIG. 1, a second ceramic green sheet 12 is laminated on the upper surface of the first ceramic green sheet 11. At this time, the opening surface above (one end) the first through hole 11a is closed by the second surface side connection pad 14a on the lower surface of the second ceramic green sheet 12, and the lower surface of the first ceramic green sheet 11 is closed. Two-side recess 11b
(Step 18). Next, the laminated first and second ceramic green sheets 1
1 and 12 are fired at a maximum temperature of about 1,550 ° C. in a reducing atmosphere to be integrated (step 20). By this firing,
First and second ceramic green sheets 11 and 12
Are ceramic first and second substrates 11, respectively.
c, 12c. Subsequently, the second surface side recess 11
b, nickel plating is applied to the metallized layer on the inner peripheral surface and the bottom surface to form a nickel plated layer 14h.
2). Through these steps, as shown in FIG.
The relay substrate body 9 in which the second substrate 12c is stacked on the first substrate 11c is completed.

In the first embodiment, the relay board main body 9 is formed in a substantially square shape having a thickness of 0.3 mm and a side of 25 mm. In addition, the first and second through holes 11
The inner diameters of a and 12a are 0.8 mm and 0.2 mm, respectively.
It is. Therefore, when removing the sheet 18 after filling the second through holes 12a of the second ceramic green sheet 12 with the conductive metal 12b in the step 12, a part of the filled conductive metal 12b is attached to the sheet 18. Poor filling of the conductive metal caused by sticking or falling off can be reduced. Also, the second surface side recess 11b is
A total of 36, 19 pieces each in a grid pattern at a pitch of 1.27 mm
One is formed. Note that a gold plating step may be provided after the above plating step, and a gold plating layer for preventing oxidation may be formed on the nickel plating layer.

Next, as shown in FIG. 1 (D), the first substrate 11c is fixed to the bottom surface and the inner peripheral surface of each second surface side concave portion 11b, and the tip protrudes from the second surface. The column-shaped second surface side connection terminals 13 are formed. Here, a method of forming the second surface side connection terminal 13 will be described with reference to FIGS. FIGS. 3A and 3B are cross-sectional explanatory views showing a step of forming the second-surface-side connection terminals 13.
FIG. 4 is an explanatory cross-sectional view showing a state where the second surface side connection terminal 13 is formed. In order to form the second surface side connection terminal 13, FIG.
Is used. The jig 40 has heat resistance,
Further, it is formed of a material that does not wet the molten high-temperature solder, for example, carbon. As shown in FIG. 3B, concave portions 41 are formed at positions corresponding to the respective second surface side concave portions 11b when the jig 40 is arranged below the relay board main body 9. The concave portion 41 is formed in a shape corresponding to the outer shape of the second surface side connection terminal 13, and is formed in a cylindrical shape having a conical bottom. Further, a gas vent hole 42 is formed to penetrate from the center of the bottom of the concave portion 41 toward the bottom surface of the jig 40. In the first embodiment, the maximum diameter of the concave portion 41 is 0.9 mm, and the maximum depth is 1.95 mm. The diameter of the gas vent hole 42 is 0.2 mm.

First, as shown in FIG.
High-temperature solder (Pb), which is a metal material of the present invention,
90% -Sn10%) high-temperature solder balls 13c.
Put each one. Next, the concave portion 4 is formed at the upper end of each concave portion 41.
The high-temperature solder balls 13d made of a high-temperature solder having a diameter slightly larger than the maximum diameter of No. 1 are respectively loaded (the metal material accommodating step of the present invention, step 24). The high-temperature solder ball 13
d is put by the following method. That is, FIG.
As shown in FIG. 7, a regulating plate 45 having a through hole (through hole) 44 having a diameter slightly larger than the diameter of the high-temperature solder ball 13d.
Is prepared, and this is arranged above the jig 40. When the high-temperature solder balls 13d are scattered on the regulating plate 45 and held and shaken so that the positional relationship between the jig 40 and the regulating plate 45 is not shifted, the high-temperature solder balls 13d roll on the regulating plate 45 and successively. It falls into the through hole 44 and cannot be moved. Then, when the high-temperature solder balls 13 d fall into all the through holes 44, the unnecessary high-temperature solder balls 13 d on the regulating plate 45 are removed, and as shown in FIG. High temperature solder ball 13
d.

At this time, as shown in FIG. 3A, the high-temperature solder ball 13c and the high-temperature solder ball 13d already placed in the recess 41 do not come into contact with each other, and when the high-temperature solder described later is melted, The spacing is slightly spaced so that the solder balls come into contact. That is, the high-temperature solder ball 13d is located under the high-temperature solder ball 13d.
When the high-temperature solder ball 13c is pushed up by the head of the high-temperature solder ball 13d, the high-temperature solder ball 13d separates from the upper end edge of the concave portion 41 and becomes unstable.
By leaving an interval with the high-speed solder ball 13d, the high-temperature solder ball 13d comes into close contact with the upper end edge of the concave portion 41 and does not move (or hardly moves). As a result, FIG.
As shown in (B), the positioning when the lower end edge of the second surface side concave portion 11b of the relay board main body 9 is put on the head of the high-temperature solder ball 13d is facilitated.

Then, as shown in FIG. 3B, the jig 40 is arranged so that the lower end of the second surface side concave portion 11b of the relay board main body 9 rides on the head of each high-temperature solder ball 13d (the present invention). Jig arrangement step, step 26). Next, the relay board main body 9 is pressed (downward) toward the upper surface 43 of the jig 40 by a load plate (not shown). Next, they are put into a reflow furnace, and the high-temperature solder balls 13c, 1c are placed in a nitrogen atmosphere at a maximum temperature of 360 ° C. and a maximum temperature holding time of 1 minute.
3c and 13d are melted (step 28). Then, the molten high-temperature solder 13d flows into the second-surface-side recess 11b of the relay board main body 9 pushed down, and
The tungsten layer 17b formed on the inner peripheral surface of the second surface side recess 11b and the second surface side connection pad 14d formed on the bottom surface of the second surface side recess 11b are welded.

The high-temperature solder balls 13c, 13c
Is melted in the concave portion 41, welded to the melted high-temperature solder 13d, and integrated. Thereby, the second surface side connection terminal 13 is formed inside the concave portion 41. When the high-temperature solder balls 13c, 13c, and 13d are melted, the air trapped in the recess 41 is released to the outside of the jig 40 through the gas vent hole 42. Subsequently, when the high-temperature solder is solidified by cooling, as shown in FIG.
b is fixed to the inner peripheral surface and the bottom surface of the second surface side concave portion 11b, and the protruding portion 13a is formed on the second surface 9b of the relay substrate main body 9.
The second surface side connection terminal 13 protruding from is formed. Then, when the jig 40 is removed, as shown in FIG.
A plurality of second surface side connection terminals 13 are formed so as to protrude from a second surface (lower surface) 9b of the relay substrate body 9, and a first surface (upper surface) is formed.
The relay board 10 in which the first surface side connection pads 14d are formed on 9a is completed (the molding step of the present invention, step 30). The second surface side connection terminal 13 is formed in a substantially columnar shape corresponding to the inner peripheral surface shape of the concave portion 41, and the lower portion (top) is formed in a substantially hemispherical shape.

In the first embodiment, the diameter of the high-temperature solder ball 13c is 0.8 mm, and the diameter of the high-temperature solder ball 13d is 1.0 mm. Further, the thickness of the regulating plate 45 is 0.5 mm, and the diameter of the through hole 44 is
1.2 mm. Further, the second surface 9 of the relay board body 9
The projecting portion 13a, which indicates a portion projecting from b, has a cross-sectional diameter (maximum diameter) of 0.88 mm and a projecting height H of 1.10 mm.
75 mm and the protrusion height is larger than the diameter.

Step 10 corresponds to the through hole forming step of the present invention, and step 12 corresponds to the via forming step. Step 14 corresponds to the metallization layer forming step, and Step 1
Reference numeral 8 corresponds to the laminating step. Step 20 corresponds to a firing step, and steps 26 to 30 correspond to a second-surface-side connection terminal forming step.

Next, a method of connecting the relay board 10 manufactured by the above-described manufacturing method to the LGA type board and the printed board will be described with reference to FIGS. FIG.
(A) is a sectional explanatory view showing a state in which the relay board 10 is connected on a printed board, and (B) is a view (A) of the same figure.
FIG. 5 is an explanatory cross-sectional view showing a state where an LGA type substrate is connected to the relay substrate 10 shown in FIG. FIG. 6 is an explanatory cross-sectional view showing a state in which the LGA type substrate and the printed circuit board are connected via the relay board 10, and FIG. 7 is a partially enlarged cross-sectional explanatory view showing a part of FIG. is there. FIG. 8 shows the relay board 10
FIG. 4 is an explanatory view showing a state where a second surface side connection terminal 13 is deformed by stress generated between printed circuit boards. In addition,
5 and FIG. 6, a portion indicated by a broken line indicates the relay board 1
This is the part where the middle of 0 is omitted.

The printed circuit board 30 used in the first embodiment
Is a 1.6mm thick, 30mm side, almost square shape,
It is made of glass epoxy (JIS: FR-4), and on the upper surface 31, the second surface side connection terminal 1 of the relay board 10 is provided.
The surface connection mounting pad 32 is formed at a position corresponding to 3. The surface connection mounting pads 32 are formed of copper (Cu) having a thickness of 25 μm, have a diameter of 0.72 mm, and have a pitch of 1.27 mm and a total of 19 pieces each of which are arranged vertically and horizontally in a grid pattern.
61 are formed.

The LGA type substrate 20 is formed of alumina ceramic, and has an IC chip accommodating portion 23 for accommodating an IC chip. On the lower surface 21 of the LGA type substrate 20, surface connection pads 22 are formed. The surface connection pads 22 have a diameter of 0.86 mm, and are formed in a grid shape with a pitch of 1.27 mm, i.e., a total of 361 in each of 19 rows and columns. The surface connection pad 22 is formed by electroless Ni-B plating on the underlying molybdenum (Mo) layer, and is further thinly electroless gold-plated to prevent oxidation. Further, the thermal expansion coefficient α of the printed circuit board 30 is
15 to 20 × 10 ⁻⁶ , and the coefficient of thermal expansion α of the LGA type substrate 20 and the relay substrate is α = 8 × 10 ⁻⁶ .

First, the low melting point solder paste 10a is
A low-melting solder paste 10b is applied to the protruding portions 13a of the surface-side connection terminals 13 on the first surface-side connection pads 14d, respectively.
It is applied in a thickness of 50 μm (low melting point metal layer forming step of the present invention). Next, as shown in FIG.
On the printed circuit board 30. At this time, the surface connection mounting surface connection mounting pad 32 formed on the printed circuit board 30 is formed.
And the projection 13a of the second surface side connection terminal 13 are aligned. Thereby, the relay board 10 and the printed board 30
Is temporarily fixed by the adhesive force of the low melting point solder paste 10a. Next, the LGA type substrate 20 is placed on the relay substrate 10. At this time, the surface connection pads 22 formed on the lower surface of the LGA type substrate 20 and the first surface side connection pads 1
The alignment with 4d is performed. As a result, the LGA type substrate 20 and the relay substrate 10 are temporarily fixed by the adhesive force of the low melting point solder paste 10b.

Next, the above connected LGA type substrate 20,
The relay substrate 10 and the printed circuit board 30 are put into a reflow furnace, and are placed in a nitrogen atmosphere (200 ° C
The above holding time is 2 minutes), and the low melting point solder paste 10a,
The low melting point solder layers 10c and 10d are formed as shown in FIG. 6 and FIG. As a result, as shown in the figure, the surface connection pad 22 includes the first surface side connection pad 14 d and the protrusion 1 of the second surface side connection terminal 13.
3a is soldered to the surface connection mounting pad 32, respectively. In the first embodiment, the low melting point solder paste 1 is used.
As 0a and 10b, a eutectic solder paste having a lower melting point than the high-temperature solder for forming the second surface side connection terminals 13 is used. Thereby, when the low melting point solder pastes 10a and 10b are melted in the reflow furnace, the second surface side connection terminals 13 are not melted. In this way, the LGA type board 20 and the printed board 30 are electrically connected via the relay board 10. The distance L (see FIG. 7) between the lower surface of the relay substrate 10 and the upper surface 31 of the printed circuit board 30 is 0.44
mm. In addition, low melting point solder pastes 10a, 10a
Since b contains flux, the surface connection pad 22 and the surface connection mounting pad 32 do not have to be prevented from being oxidized by a gold plating layer or the like.

In an electronic device, such as a computer, having the above-mentioned LGA type board 20, relay board 10 and printed circuit board 30, heat generated from a power supply unit or the like generates heat from LGA type board 20, relay board 10 and printed circuit board 3.
0, the relay board 10 and the printed board 30
A stress is generated between the two substrates due to a difference in thermal expansion based on the difference in the material of the two substrates. As shown in FIG. 7, this stress is caused by contact portions P1 and P2 where the base 13b of the second surface side connection terminal 13 and the inner peripheral surface of the second surface side recess 11b are in contact with each other. It occurs at the connection between the protrusion 13a and the low melting point solder layer 10c. However, since the protrusion 13a is formed of high-temperature solder and is soft, it easily undergoes plastic deformation as shown in FIG.
The stress is alleviated by the plastic deformation of 3a. Therefore, there is no possibility that the low melting point solder layers 10c and 10d are broken. Also, the LGA type substrate 20 and the relay substrate 10
Are made of the same material and have no difference in thermal expansion.
Almost no stress is generated between the mold substrate 20 and the relay substrate 10. For this reason, cracks do not occur in the low melting point solder layer 10d where cracks are most likely to occur in the past, and there is no risk of breakage.

As described above, using the relay board 10 of the first embodiment, the LGA type board 20 and the printed board 30
Is electrically connected, the stress generated by the difference in thermal expansion between the substrates can be absorbed.
There is no danger that the connection portion between the mold substrate and the printed circuit board will be broken and electrical connection failure will occur. Therefore, the reliability of the electrical connection between the LGA type board 20 and the printed board 30 can be improved by using the relay board 10 and the method of manufacturing the same according to the first embodiment. Further, even when the magnitude of the stress generated differs depending on the board to which the relay board 10 is connected, the depth of the concave portion 41 of the jig 40 is adjusted to change the protruding height of the second surface side connection terminal 13. Can be dealt with. For example, when the stress is large, the protruding height of the second surface side connection terminal 13 is increased, and when the stress is small, it is decreased.

Next, a relay board and a method of manufacturing the same according to a second embodiment of the present invention will be described with reference to FIGS. The relay board and the method of manufacturing the same according to the second embodiment are characterized in that the diameters of the first and second through holes are the same. FIGS. 10A to 10D are explanatory views showing the steps of manufacturing the relay board of the second embodiment.
11 is a partial cross-sectional explanatory view showing a part of a cross section of a structure in which an LGA type substrate and a printed circuit board are connected by a relay substrate manufactured by the manufacturing process shown in FIG.

First, the first ceramic green sheet 1
The first through-hole 15a and the second through-hole 16a are formed at a time by a punching apparatus in a state where the fifth and second ceramic green sheets 16 are stacked. This allows
Since the number of steps for forming the through holes may be one, two steps for individually forming the through holes in the first and second ceramic green sheets 11 and 12 are required as in the manufacturing method of the first embodiment. The number of steps can be reduced by one.

Next, the second ceramic green sheet 1
The conductive metal 16 is provided in each second through hole 16a formed in
Fill b. Thereafter, by the same steps as Steps 14 to 30 of the first embodiment, as shown in FIG. 10D, the second surface side connection terminals 13 protrude from the second surface (lower surface) 51b of the relay board main body 51. The relay board 50 is formed. In this case, as shown in FIG. 10D, the via 16d, the first surface side connection pad 14d, and the second surface side connection pad 14c have the same diameter, and the contact area between the via and the connection pad is the first embodiment. Since it is larger than in the case of the form, the electric resistance can be reduced. Then, the relay substrate 50 thus formed is connected to the LGA type substrate 2 by the same connection method as described in the first embodiment, as shown in FIG.
0 and the printed circuit board 30.

In the above connection state, when stress is generated due to a difference in thermal expansion between the relay board 50 and the printed board 30, the second surface side connection terminal 13 is plastically deformed by the stress, and the stress is relaxed by the plastic deformation. Is done. Therefore, there is no possibility that the low melting point solder layers 10c and 10d are broken. Also, the LGA type substrate 20 and the relay substrate 5
0 is the same material, and there is no difference in thermal expansion.
Almost no stress is generated between the A-type substrate 20 and the relay substrate 50.

As described above, the LGA type substrate 20 and the printed circuit board 30 are formed by using the relay substrate 50 of the second embodiment.
Is electrically connected, the stress generated by the difference in thermal expansion between the substrates can be reduced.
There is no danger that the connection portion between the mold substrate and the printed circuit board will be broken and electrical connection failure will occur. Therefore, the reliability of the electrical connection between the LGA type board 20 and the printed board 30 can be improved by using the relay board 50 and the method of manufacturing the same according to the second embodiment.

Next, a relay board according to a third embodiment of the present invention and a method for manufacturing the same will be described with reference to FIG. In the relay board and the method of manufacturing the same according to the third embodiment, the inner peripheral surface of the second-surface-side concave portion is formed in a tapered shape (conical shape), and has a cylindrical shape as in the first and second embodiments. It is characterized in that the stress applied to the portion where the connection terminal and the inner peripheral surface are in contact with each other can be dispersed more than the relay substrate having the concave portion. FIG. 14 is a cross-sectional view of the relay board according to the third embodiment.
FIG. 3 is a partial cross-sectional explanatory view showing a part of a cross section of a structure in which a GA type substrate and a printed circuit board are connected.

First, the relay board main body 83 is manufactured (FIG. 9).
Steps 10 to 22). In this case, in the first ceramic green sheet, a first through hole having an inner peripheral surface tapered is formed. The first through hole is formed using, for example, an excimer laser or a mold. The energy distribution of the excimer laser is the largest on the irradiation surface of the first ceramic green sheet, and becomes smaller as it proceeds in the thickness direction of the first ceramic green sheet, so that the inner peripheral surface of the first through hole is tapered. Can be formed.

Next, using the jig 40 (see FIG. 3) used in the first embodiment, the second surface side connection terminal 8 is inserted into the second surface side recess.
2 (Steps 24 to 30 in FIG. 9). By these steps, as shown in FIG. 14, the first substrate 81c
The relay substrate 83 having the second-surface-side connection terminals 82 protruding from the lower surface (second surface) 83b of the second substrate is completed. The second surface side connection terminal 82 has a columnar protrusion 82a protruding from the lower surface 83b of the first substrate 81c and a base 82b fixed in the second surface side recess 81b. The base 82b is formed of a tungsten layer 17e. The upper nickel plating layer allows the tapered second
Fixed to the inner peripheral surface of the surface-side concave portion 81b;
It is fixed to the bottom surface of the second surface side recess 81b by a nickel plating layer on the surface side connection pad 14e. Also, the first
Surface-side connection pad 14d and second surface-side connection pad 14e
Are electrically connected by vias 12d formed in the second substrate 12c. Then, the relay board 80 thus formed is connected to the LGA type board 20 and the printed board 30 by the same connection method as described in the first embodiment, as shown in FIG.

In the above connection state, the relay board main body 83
When a stress is generated due to a difference in thermal expansion between the printed circuit board 30 and the second substrate side connection terminal 8 so as to absorb the stress.
Since 2 is plastically deformed, the stress is relaxed by the plastic deformation. In particular, since the inner peripheral surface of the second surface side concave portion 81b is formed in a tapered shape, stress is applied to the second surface side connection terminal 82.
(Corner) P6 where the edge of the second surface side recess 81b contacts
Stress can be dispersed over the entire surface of the tapered surface P3.

As described above, the LGA type substrate 20 and the printed circuit board 30 are formed using the relay substrate 80 of the third embodiment.
Is electrically connected, the stress generated by the difference in thermal expansion between the substrates can be reduced.
There is no danger that the connection portion between the mold substrate and the printed circuit board will be broken and electrical connection failure will occur. In particular, since the inner peripheral surface of the second surface side concave portion 81b is formed in a tapered shape,
It is possible to realize a highly durable relay board that is less likely to be broken by stress than the relay boards of the first and second embodiments. Therefore, the reliability of the electrical connection between the LGA type substrate 20 and the printed circuit board 30 can be further improved by using the relay board and the method of manufacturing the same according to the third embodiment.

Next, a relay board and a method of manufacturing the same according to a fourth embodiment of the present invention will be described with reference to FIG.
The relay board according to the fourth embodiment is characterized in that the inner peripheral surface of the second surface side recess is formed in a step shape. FIG.
FIG. 3 is a partial cross-sectional explanatory view showing a part of a cross section of a structure in which an LGA type substrate and a printed circuit board are connected by the relay substrate of the embodiment.

As shown in FIG. 15, the relay board 90 of the fourth embodiment has a relay board body 94 formed by sequentially stacking a first board 91c, a second board 92c, and a third board 12c. . The diameter of the through-hole formed in the first substrate 91c is larger than the diameter of the through-hole formed in the second substrate 92c. That is, by laminating the substrates on which the through holes having different diameters are formed, the second surface side recess 91b having the step-shaped inner peripheral surface is formed.

The second surface side connection terminal 93 is formed in the second surface side recess 91b formed inside the first substrate 91c and the second substrate 92c. The second surface side connection terminal 93 is provided on the lower surface (first surface) 9 of the first substrate 91c.
4b has a protruding portion 93a protruding from the base 93b.
Is fixed to the inner peripheral surface of the second surface side recess 91b by a nickel plating layer on the tungsten layer 17g, and the second surface side recess 91b is fixed by the nickel plating layer on the second surface side connection pad 14g. It is fixed to the bottom.

When stress is generated due to a difference in thermal expansion between the relay board main body 94 and the printed circuit board 30, the second surface side connection terminal 93 is plastically deformed so as to absorb the stress. Be relaxed. Especially,
Since the inner peripheral surface of the second surface side concave portion 91b is formed in a step-like shape, stress can be dispersed to two points of the inner peripheral surface at corners P4 and P5. Therefore, when the relay board 90 of the fourth embodiment is used, it is less likely to be broken and has higher durability than the relay board of the first and second embodiments in which the stress is easily concentrated at one point of P1. A relay board can be realized.

In the first embodiment, the jig 40 shown in FIGS. 3 and 4 is used in the second-surface-side connection terminal forming step for forming the second-surface-side connection terminals 13. A jig 60 shown in FIG. The jig 60 has a diameter corresponding to the diameter of the protruding portion 13a of the second surface side connection terminal 13 and has a through hole 61 having an inner surface that is not wet with the molten metal at a position corresponding to the second surface side recess 11b. Respectively. When this jig 60 is used, as shown in FIG.
The jig 6 is arranged such that the opening side of the surface side recess 11b faces upward, and the second surface side recess 11b and the through-hole 61 correspond to each other.
0 is arranged above the relay board main body 9 (jig arrangement step).

Next, two or three high-temperature solder balls 13e are charged from above each through-hole 61 (metal material accommodating step), and the high-temperature solder ball 13e is heated and melted in a reflow furnace. While being held in the inside 61 and the second surface side recess 11b, it is cooled and solidified to form the second surface side connection terminal 13 (forming step). The relay substrate having the second surface side connection terminals 13 formed by this method is also the same as the relay substrate in each of the above embodiments, and the LGA type substrate 2
0 and the printed circuit board 30, and the generated stress can be reduced by plastic deformation of the second surface side connection terminal. Note that the second surface side connection terminals of the second to fourth embodiments can also be manufactured by a method using the jig 60.

The tip of the second surface side connection terminal is usually
Although it is formed in a hemispherical shape by the surface tension of the molten solder, it may be formed on a flat surface. Thereby, the contact area between the tip of the second surface side connection terminal and the surface connection attachment pad can be increased, so that the adhesive force between the tip of the second surface side connection terminal and the surface connection attachment pad can be increased. it can. Therefore, when an impact occurs when the relay board is placed at a predetermined location, or when vibration occurs when the relay board is moved or when the relay board moves in the solder reflow furnace, the second surface side connection is performed. Since the lateral displacement is less likely to occur between the tip of the terminal and the surface connection mounting pad, the relay substrate and the substrate or the mounting substrate can be securely connected. As a method of forming the tip of the second surface side connection terminal on a flat surface, a method of polishing and removing the top of the second surface side connection terminal, a method of pressing the top of the second surface side connection terminal, etc. There is.

In each of the above embodiments, the relay board and the method of manufacturing the relay board according to the present invention have been described as representatively used for electrically connecting an IC chip mounting board and a printed board. The present invention can also be applied to a device for electrically connecting substrates having the same. Further, the second ceramic green sheet constituting the via is constituted by two or more ceramic green sheets,
A through hole may be formed in each of the ceramic green sheets, and a via may be formed in each of the through holes to be laminated. Furthermore, the first ceramic green sheet forming the second surface side concave portion may also have a configuration in which two or more ceramic green sheets having through holes are formed.

Further, as the metal forming the via, a conductive metal other than tungsten and molybdenum, for example, a solder material can be used. Further, unlike the second surface connection terminal in each of the above embodiments, the base is not fixed in the second surface recess, but the base is fixed on the second surface of the relay board main body. Can also. In this case, the bases of the second surface side connection terminals are connected via vias and pads filled in the through holes of the relay board main body,
With this configuration also, stress can be reduced by plastic deformation of the second surface side connection terminal.

In each of the above embodiments, an example was shown in which alumina ceramic was used as the material of the relay substrate body. However, the present invention is not limited to this, and aluminum nitride, silicon nitride, silicon carbide, mullite and other materials are used. Ceramics to be formed can also be used. In particular, since a relatively high stress is applied to the relay substrate body, a material having high breaking strength and toughness may be appropriately selected. Further, depending on the material of the first substrate and the second substrate, a synthetic resin material such as glass epoxy or BT resin may be used. In particular, the first
When the substrate and the second substrate are made of resin, it is preferable that the relay substrate body is also made of resin. In this case, the material of the relay board body is changed to the first board or the second board.
It is preferable to use the same material as any one of the substrates or a material having a thermal expansion coefficient intermediate between that of the first substrate and the second substrate.

In each of the above embodiments, carbon is shown as an example of the material for forming the jig 40 and the jig 60, but any material having no wettability to the molten metal to be used may be used. , Boron nitride, ceramics such as silicon nitride, and metals such as stainless steel and titanium. In particular, since the regulating plate 45 is a plate-like body, it is preferable to use a metal such as stainless steel since cracks and the like are less likely to occur. It is also preferable in that the through holes 44 can be easily formed with high precision by etching. On the other hand, in order to reduce the coefficient of thermal expansion or prevent warpage due to heat, it is preferable to use ceramics. Further, in each of the above embodiments, the method of melting the high-temperature solder balls accommodated in the jig 40 or the jig 60 to form the second surface side connection terminals is employed. Pour the second
It is also possible to adopt a method of forming the surface side connection terminals.

[0084]

As described above, according to the present invention, the first substrate (IC chip mounting substrate) having the substrate surface provided with the surface connection pads and the substrate surface provided with the surface connection mounting pads are provided. It is possible to realize a relay board having a thermal expansion coefficient different from the thermal expansion coefficient of the first board and a reliability of electrical connection with a second board (printed board) and a method of manufacturing the same. it can.

[Brief description of the drawings]

FIGS. 1A to 1D are cross-sectional explanatory views showing each step of a method for manufacturing a relay board according to a first embodiment of the present invention.

FIG. 2A is an explanatory diagram showing a method of filling a second through hole with a conductive metal for forming a via;
(B)-(D) is an explanatory view showing a method of forming a tungsten layer on the inner peripheral surface of the first through hole.

FIGS. 3A and 3B are cross-sectional explanatory views showing a method of forming a second surface side connection terminal using a jig.

FIG. 4 is an explanatory cross-sectional view showing a state where a second surface side connection terminal is formed in a concave portion of the jig.

5A is a cross-sectional view illustrating a state in which a relay board is connected to a printed circuit board, and FIG. 5B is a cross-sectional view illustrating a state in which an LGA type board is connected to the relay board illustrated in FIG. FIG.

FIG. 6 is an explanatory sectional view showing a state where an LGA type substrate and a printed circuit board are connected via a relay substrate.

7 is a partially enlarged sectional explanatory view showing a part of FIG. 6 in an enlarged manner.

FIG. 8 is an explanatory view showing a state where the second surface side connection terminal is plastically deformed by a stress generated between the relay board and the printed board.

FIG. 9 is a process chart showing a process of manufacturing the relay board according to the first embodiment of the present invention.

FIGS. 10A to 10D are cross-sectional explanatory views showing each step of the method for manufacturing a relay board according to the second embodiment of the present invention.

11 is a cross-sectional partial explanatory view showing a part of a cross-section of a structure in which an LGA type substrate and a printed circuit board are connected by a relay substrate manufactured by the manufacturing process shown in FIG. 10;

FIG. 12 is an explanatory sectional view showing another method of forming the second surface side connection terminal.

FIG. 13 is a partial cross-sectional view showing a BGA type substrate connected to a printed circuit board.

FIG. 14 illustrates a third embodiment of the present invention;
FIG. 3 is an explanatory sectional view showing a state where an A-type substrate and a printed circuit board are connected.

FIG. 15 is a view showing an example of the configuration of an LG according to a fourth embodiment of the present invention;
FIG. 3 is an explanatory sectional view showing a state where an A-type substrate and a printed circuit board are connected.

[Explanation of symbols]

 Reference Signs List 9 relay substrate main body 9a first surface 9b second surface 10c, 10d low melting point solder layer 10 relay substrate 11 first ceramic green sheet 11a first through hole 11b second surface side recess 12 second ceramic green sheet 12a first 2 through-holes 11c first substrate 12c second substrate 12d via 13 second surface side connection terminal 13a protrusion 13b base 13c high temperature solder ball (metal material) 14c second surface side connection pad 14d first surface side connection pad Reference Signs List 20 LGA type substrate (first substrate) 30 Printed substrate (second substrate) 40, 60 jig 41 concave portion 45 regulating plate 61 through hole

Claims (15)

[Claims] 1. A first substrate having a substrate surface provided with a surface connection pad, and a thermal expansion coefficient having a substrate surface provided with a surface connection mounting pad and different from a thermal expansion coefficient of the first substrate. A relay board interposed between the second board and the second board for electrically connecting the surface connection pad and the surface connection mounting pad, wherein the relay board has a substantially plate shape having a first surface and a second surface. A relay substrate body made of an electrically insulating material, a second surface-side recess formed on the second surface toward the first surface, a bottom surface and an inner peripheral surface of the second surface-side recess. A second surface-side connection terminal that is fixed and is formed by projecting a distal end portion from the second surface, and that is electrically connected to the surface connection attachment pad; And the second surface side connection terminal and the surface connection pad are formed. Relay substrate characterized by having a a via for electrically connecting and. 2. The relay board according to claim 1, wherein an inner peripheral surface of the second surface side recess is formed in a tapered shape. 3. The relay board according to claim 1, wherein an inner peripheral surface of the second surface side recess is formed in a step shape. 4. A second surface side connection pad formed on a bottom surface of the second surface side concave portion for electrically connecting the second surface side connection terminal and the via, 4. The relay according to claim 1, further comprising: a first surface-side connection pad formed to electrically connect the via and the surface connection pad. 5. substrate. 5. The protruding portion of the second surface side connection terminal is formed in a column shape whose protruding height is larger than the maximum diameter of the protruding portion. 5. The relay board according to any one of 4. 6. The relay board according to claim 1, wherein the second surface side connection terminal is formed of a soft metal. 7. A low melting point metal layer made of a metal having a melting point lower than the melting point of the second surface side connection terminal on each of the upper surface of the first surface side connection pad and the tip of the second surface side connection terminal. The relay board according to any one of claims 4 to 6, wherein the relay board is formed. 8. The relay board body according to claim 1, wherein the relay board body has substantially the same coefficient of thermal expansion as the first board.
The relay board according to claim 7. 9. The method according to claim 1, wherein the first substrate is made of a ceramic material, and the relay substrate body is made of the same ceramic material as the first substrate. The relay board according to any one of the above. 10. The relay board according to claim 1, wherein a diameter of the via is smaller than a diameter of the second surface side recess. 11. The method for manufacturing a relay board according to claim 1, wherein a first through hole is formed in the first ceramic green sheet, and wherein the first ceramic green sheet is provided with a first through hole. A through-hole forming step of forming a second through-hole at a portion corresponding to the first through-hole of a second ceramic green sheet laminated with a green sheet; and a second through-hole of the second ceramic green sheet. A via forming step of forming the via inside the metallized layer; a metallizing layer forming step of forming a metallized layer in the first through hole; and the second ceramic green sheet and the through hole forming through the via forming step The first ceramic green sheet having undergone the step is made to correspond to the via and the first through hole, and one end of the first through hole is connected to the second ceramic green sheet. A laminating step of laminating in a state where the second surface side concave portion is formed by closing the first and second ceramic green sheets having undergone the laminating step to form the relay substrate body. A baking step; and a second-surface-side connection terminal forming step of forming the second-surface-side connection terminal inside the second-surface-side concave portion of the relay substrate main body after the baking step. A method for manufacturing a relay board. 12. A connection pad forming step of forming said first surface side connection pad and said second surface side connection pad on said second ceramic green sheet having undergone said via formation step. 3. The method for manufacturing a relay board according to 1. 13. The second-surface-side connection terminal forming step includes forming a concave portion having a shape corresponding to a shape of a protruding portion of the second-surface-side connection terminal and having an inner surface that is not wet by molten metal. A metal material accommodating step of using a jig provided at a position corresponding to the two-surface-side concave portion and accommodating a metal material for forming the second-surface-side connection terminal in the concave portion of the jig; A jig arranging step of arranging the jig having passed through the jig arranging step in a state in which the concave portion is located below the concave portion on the second surface side of the relay substrate body formed by the firing step; The metal material contained in each recess of the tool is melted, and the melted metal is cooled and solidified while being held in the recess and the second surface side recess to form the second surface side connection terminal. And a molding process. Claim to 11 or claim 12
3. The method for manufacturing a relay board according to 1. 14. The second surface side connection terminal forming step includes forming a through hole having a diameter corresponding to a diameter of a protruding portion of the second surface side connection terminal and having an inner surface which is not wetted by molten metal. Jigs each having a jig having a position corresponding to the second-surface-side concave portion are formed in the firing step, and the second-surface-side concave portion of the relay substrate main body in a state where the opening side of the second-surface-side concave portion faces upward. A jig arranging step of disposing the jig in a state where the through-hole is located above; and a metal accommodating a metal material for forming the second surface side connection terminal in the through-hole of the jig having passed through the jig arranging step. A material accommodating step; melting the metal material accommodated in the through hole of the jig after the metal material accommodating step; cooling while holding the molten metal in the through hole and the second surface side recess; And solidified to form the second surface side connection terminal 13. A molding step, comprising:
3. The method for manufacturing a relay board according to 1. 15. An upper surface of the first surface side connection pad and a tip of the second surface side connection terminal which have undergone the second surface side connection terminal forming step, each having a melting point lower than the melting point of the second surface side connection terminal. The method according to any one of claims 11 to 14, further comprising a low melting point metal layer forming step of forming a low melting point metal layer from a metal having a melting point.