JPH1140700A - Wiring board, its manufacture, and manufacture of connecting body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the positions of wring boards to be corrected naturally even when a little positional deviation exists between the wring boards when the wiring boards are connected to each other, by butting the front ends of the pins of one wiring board against the connecting pads of the other wiring board, and soldering the front ends to the pads. SOLUTION: In the main body 1 of a multilayered wiring board and a wiring board 10 having pins 7 which are fixed to many pin fixing pads 3 formed on the main surface of the main body 1 and formed in a grid-like state with silver solder 8, large-diameter sections composed of high-temperature solder balls 6 are formed at the front ends of the pins 7. The wiring board 10 is connected to a printed wiring board 20 on which connecting pads 23 are formed at the positions corresponding to the pins 7 fixed to the upper surface of the main body 21 of the wiring board 20 with solder 26. When the wiring board 10 is connected to the wiring board 20, the position of the wiring board 10 is automatically adjusted by the surface tension of the molten solder 26, and the pins 7 are positioned to nearly the centers of the connecting pads 23.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring board for connecting pins by soldering while abutting a pin against another wiring board, a method of manufacturing the same, and a connector connecting the wiring board and another wiring board. And a method for producing the same.

[0002]

2. Description of the Related Art As terminals provided for connecting a wiring board to another wiring board, leads, pins, ball-shaped terminals and the like are known, and a wiring board in which pins are provided in a wiring board body in a lattice shape. Is a PGA type wiring board, and a wiring board in which ball-shaped terminals are provided in a lattice shape is sometimes called a BGA type wiring board.

[0003] As shown in FIGS. 7 and 8, the ends of the pins 105 are soldered to the PGA type wiring board while being abutted against connection pads 123 provided on another wiring board 120, thereby connecting the two. Such a type of wiring board 100 is sometimes called a butt joint PGA type wiring board. As shown in FIG. 7, on the wiring substrate 100, a large number of pin fixing pads 103 are formed in a grid pattern on the lower main surface 101a in the figure, and the pin fixing pads 103 have a nail head shape ( A pin 105 having a nail head shape is soldered with a silver solder 108. Further, a large number of chip connection pads 109 for connecting to the integrated circuit chip 111 are formed on the upper surface 101b in the figure. The chip connecting pad 109 and the integrated circuit chip 1
The chip pad 113 provided on the chip 11 is flip-chip connected via a chip connection solder 115.

Further, the connection surface 1 of another wiring board main body 121
A connection pad 123 is formed at a position corresponding to each pin 105 on the upper surface 21a (the upper surface in the figure), and a solder paste 125 is applied on the upper surface thereof. The ends (lower ends in the figure) of the pins 105 are brought into contact with the connection pads 123 while aligning them, and then the solder paste 12
8, the tip of the pin 105 and the connection pad 123 are soldered by the pin connection solder 126, as shown in FIG.
Are connected.

[0005]

Further, in the butt joint PGA type wiring board 100, the wiring board main body 101 and the other wiring board main body 121 are connected with an interval corresponding to the length of the pin 105. Is done. Therefore,
Since the material of the wiring board main body 101 and the material of the other wiring board main body 121 are different, a difference in thermal expansion is generated between the two.
When a relative displacement occurs between the two, the pin 105 between the two is bent to absorb a displacement such as a difference in thermal expansion,
The pin 105 may be broken, or the pin 105 and the connection pad 12 may be broken.
Inconveniences such as disconnection at the connection portion with 3 are less likely to occur.
For this reason, a highly reliable connection becomes possible.

However, such a butt joint PG
In the A-type wiring board 100, as shown in FIG. 9, in connection between the wiring board 100 and another wiring board 120,
There has been a problem that displacement is likely to occur. That is, in the connection between the two, it is necessary to accurately position and connect the position of each pin 105 with respect to each connection pad 123, that is, the position of the wiring board main body 101. When they are aligned (butted) in a state where both positions are shifted, as shown in FIG.
This is because each pin 105 may be connected to the connection pad 123 while being shifted in the horizontal direction. Further, even if the positioning is performed accurately, there may be a case where a displacement occurs due to an impact or the like during the subsequent handling or during the process of moving the inside of the belt furnace to melt the solder paste.

As described above, if the position of the pin 105 is shifted with respect to the connection pad 123, a difference in thermal expansion between the wiring board main body 101 and the other wiring board main body 121 due to a temperature change may occur. In addition, a lateral stress is applied to the pin, and the pin 105 is easily detached from the connection pad 123, so that the connection reliability is reduced. Further, the displacement becomes extremely large, and the pin 105
Of the connection pad 123, the insulation distance between the connection pad 123 and the insulation resistance is reduced.
It is also conceivable that some of them are not connected to the device 23.

The present invention has been made in view of such a problem, and when connecting a wiring board to another wiring board using pins protruding from the wiring board, there is a slight displacement. Even so, it is an object of the present invention to provide a wiring board in which both positions are naturally corrected and connected. It is another object of the present invention to provide a method for manufacturing the wiring board and a method for manufacturing a connection body between the wiring board and another wiring board.

[0009]

However, the solution is to provide a wiring board body having at least one main surface and a large number of pins protruding from the main surface. A wiring board for connecting to another wiring board by soldering using pin connection solder while abutting a connection pad formed on the wiring board of the above, wherein the pins are
The gist of the present invention is to provide a wiring board having a large-diameter portion made of a material that does not melt at the time of soldering the pin connection solder at the tip thereof.

[0010] Here, the wiring board main body has wiring on one side or both sides, a multilayer wiring board having vias and through holes for connecting the wiring and the wiring of each layer, and a via between the both sides. A connection through a through hole and the like can be given. The material is also alumina, Al
N, ceramic such as glass ceramic, resin such as epoxy resin, BT resin, polyimide resin, composite material such as glass-epoxy resin, glass-BT resin, composite material of ceramic and resin, or ceramic such as alumina A material in which an insulating layer is formed with a resin on a substrate or a glass-BT resin composite material substrate may be used. In addition, the wiring board body may be for mounting electronic components such as an integrated circuit chip, a semiconductor element, a capacitor, and a resistor.
In addition, a relay wiring board (relay board) for relaying between two wiring boards may be used.

The pins only need to protrude from the main surface of the wiring board. For example, the pins may be fixed by brazing to pads provided on the main surface. The pins may be inserted through the back surface of the main surface of the substrate body and the pins may be protruded from the main surface. The pin material may be appropriately selected in consideration of the material of the wiring board body, etc.
For example, 42 alloy (42% Ni-Fe alloy) and Kovar (Fe-N
i-Co alloy) or a copper alloy can be selected. In addition, in consideration of corrosion resistance, solderability, and the like, a pin may be formed with a coating of Ni, Au, or the like on a pin body made of these materials by plating or the like.

In addition to other wiring boards having wiring on one side or both sides, there are also multilayer wiring boards having vias and through holes for connecting wiring and wiring between layers, and vias and through holes between both sides. A connection through a hall and the like can be given. The material is also ceramics such as alumina, AlN, glass ceramic, epoxy resin, BT resin, resin such as polyimide resin, glass-epoxy resin,
A composite material such as glass-BT resin, a composite material of ceramic and resin, or a ceramic substrate such as alumina or a glass-BT resin composite material substrate on which an insulating layer is formed with resin may be used.

According to the above-mentioned means, since the tip end of the pin which abuts against another wiring board has a large-diameter portion, the connection pad of the other wiring board and this large-diameter portion are soldered using the solder for pin connection. In this case, the connection (contact) area of the solder increases. At this time, if the positions of the pins and the connection pads are misaligned, a force is exerted on each of the pins so as to position the pins approximately at the center of each of the pads, due to surface tension that attempts to reduce the surface area of the molten solder. These forces overlap (combined) to provide a force for moving the wiring board. That is, even when the connection work is started in a state where the position of the wiring board main body and the position of the other wiring board main body are slightly deviated, the wiring board or other wiring is naturally formed so as to have a correct positional relationship by the surface tension of the molten solder. A self-alignment effect in which the wiring board relatively moves is generated, and the two can be reliably connected.
Therefore, when the wiring board of the present invention is connected to another wiring board, the two can be reliably connected even if the positioning of the two is relatively rough. Further, even if a displacement occurs due to an impact or the like during melting of the solder paste, the displacement is automatically repaired.

In addition, since the wiring board main body and the other wiring board main body are connected by a pin having a small diameter, displacement caused by a difference in thermal expansion between the two is absorbed by bending of the pin. In addition, since the diameter of the pin is large at the tip, the connection area with the solder increases, so that the solder and the pin can be more reliably connected and the connection reliability can be further improved.

Further, in order to achieve the above object, according to a second aspect of the present invention, the large diameter portion is made of a solder having a melting point higher than that of the pin connection solder. The wiring board described above is the gist.

According to this means, when the pin connection solder is melted to solder the pin and the connection pad, the large diameter portion does not melt, so that when the pin connection solder melts, The wiring board can be connected to another wiring board at a correct position by the tension. In addition, since the large-diameter portion is made of solder, the large-diameter portion at the tip of the pin and the pin-connection solder are firmly connected to each other so that the pin-connection solder is well wetted and integrated, thereby further improving connection reliability. Can be.

Further, in order to achieve the above object, according to a third aspect of the present invention, there is provided a fixing device according to the second aspect, wherein a solder flow preventing portion is formed adjacent to a large-diameter portion at the tip of the pin. The gist of the wiring board is as follows.

According to this means, since the solder flow preventing portion is formed adjacent to the large-diameter portion, when the large-diameter portion is formed by solder, the solder flows from the tip of the pin to the wiring board body side and spreads. There is no. Therefore, since the amount of solder at the large diameter portion at the tip of the pin is constant, the dimension of the large diameter portion is constant, and the surface tension applied to each pin during connection with another wiring board is also uniform, thereby reducing the displacement. It can be surely eliminated. Also, when connecting to another wiring board, the solder for pin connection does not exceed the large diameter part and does not spread to the wiring board body side, and the amount of solder for pin connection that is involved in the connection between each pin and the pad should be constant. Therefore, the surface tension applied to each pin is also uniform from this point, and the displacement can be more reliably eliminated.

Further, in order to achieve the above object, a solution according to a fourth aspect of the present invention is to provide the solder flow preventing portion, wherein a pin peripheral surface adjacent to a large diameter portion of the pin tip is a solder non-wetting surface. The gist is the wiring board according to claim 3.

Here, the solder non-wetting surface is a surface which is formed of a material which does not wet the solder constituting the large diameter portion at the tip of the pin and the solder for connecting the pin, or has been treated so as not to wet these solders. Specifically, for example, a surface formed by a nickel oxide layer, a blackened nickel layer, a chromium plating layer, or the like formed by a thermal oxidation treatment or the like can be given.

According to this means, it is possible to reliably prevent the solder from spreading to the wiring board body side due to the solder non-wetting surface when forming the large-diameter portion, so that the shape of the large-diameter portion can be made constant. In addition, it is possible to prevent the solder for pin connection from spreading beyond the large-diameter portion to the wiring board main body side during connection with another wiring board.

According to a fifth aspect of the present invention, in order to achieve the above object, a solder non-wetting material is formed on the peripheral surface of the pin adjacent to the large diameter portion at the tip of the pin as the solder flow preventing portion. The gist of the invention is a wiring board according to claim 3.

Here, the solder non-wetting material refers to a material which does not wet the solder constituting the large diameter portion at the tip of the pin and the solder for connecting the pin. Specifically, for example, epoxy resin, acrylic resin A resin such as a solder resist such as a solder resist which repels solder, glass and the like can be used.

According to this means, it is possible to reliably prevent the solder from spreading to the wiring board main body side by the solder non-wetting material at the time of forming the large diameter portion, so that the shape of the large diameter portion can be made constant. In addition, it is possible to prevent the solder for pin connection from spreading beyond the large-diameter portion to the wiring board main body side during connection with another wiring board.

According to a sixth aspect of the present invention, in order to achieve the above object, a brim portion made of a material of a pin body is provided as the solder flow preventing portion adjacent to a large-diameter portion at the tip of the pin. The gist of the invention is a wiring board according to claim 3.

The term "flange" as used herein refers to a portion of the pin body having a larger diameter in the radial direction than the normal diameter of the pin body.
Shape, or a shape in which the diameter of a part of the wiring board body side is slightly larger than the tip. The planar shape of the flange is suitably a disk (column), but may be a square, hexagon, cross, or the like.

According to this means, even when the solder tends to spread from the tip of the pin to the wiring board body at the time of forming the large-diameter portion, the solder is hard to spread to the board body because the area of the flange is large. Therefore, the spread of the solder can be reliably prevented by the flange portion, so that the shape of the large-diameter portion can be made constant. In addition, it is possible to prevent the solder for pin connection from spreading beyond the large-diameter portion to the wiring board main body side during connection with another wiring board. In addition, since it is sufficient that the pin is provided with a flange portion before being fixed to the wiring board, there is no need to form a solder non-wetting surface or a solder non-wetting material on the pin after fixing, and it is possible to reliably and easily Can be formed.

According to a seventh aspect of the present invention, in order to achieve the above object, the pin is a pin having a pin body having a tip with a large diameter.
The gist is the wiring board described in.

According to this means, the large diameter portion at the tip of the pin is
Since the tip of the pin body itself has a large diameter, it is not necessary to form a large diameter portion at the tip of the pin after projecting the pin from the wiring board body. Therefore, an inexpensive wiring board can be obtained. Further, since the large diameter portion is made of the same material as the pin main body, even if the soldering temperature at the time of connection between the pin and the pad is slightly increased, the pin main body itself does not melt. Therefore, even if the soldering temperature is not strictly controlled, the connection can be surely made.

Further, in order to achieve the above object, a solution according to claim 8 is that the maximum diameter of the large diameter portion of the pin is:
8. The semiconductor device according to claim 1, wherein a diameter of the connection pad formed on said another wiring board is 0.7 to 1.4 times as large as that of said connection pad for connection with said pin. The gist of the wiring board is as follows.

Since the self-alignment effect in which the wiring board and the other wiring board relatively move is caused by the surface tension of the molten solder for pin connection, the diameter of the large-diameter portion and the diameter of the connection pad become large. The effect increases when they are approximately the same size,
If one is small, the effect is considered to be small.
That is, when the diameter of the large diameter portion is smaller than 0.7 times the diameter of the pad, the cross-sectional area of the large diameter portion becomes approximately 1/2 of the cross-sectional area of the connection pad when compared with the area. The surface tension generated therebetween is small, and it is difficult to expect a self-alignment effect of automatically eliminating the displacement. Similarly,
When the diameter of the large diameter part is larger than 1.4 times the diameter of the pad,
The cross-sectional area of the large-diameter portion is about twice the area of the connection pad, the surface tension acting between them becomes small, and the self-alignment effect is hardly expected. Therefore, according to the above means, the self-alignment effect can be sufficiently obtained. If the diameter of the large-diameter portion is too large, the distance between the pins becomes small and the insulation distance becomes short, which is not preferable. Therefore, the diameter of the large-diameter portion is preferably selected in consideration of the distance between the pads.

According to another aspect of the present invention, there is provided a wiring board body having at least one main surface and a plurality of pins projecting from the main surface. A method of manufacturing a wiring board comprising a large-diameter portion made of a material that does not melt during soldering of the pin connection solder at the tip of the pin, wherein a solder having a higher melting point than the pin connection solder is welded to the tip of the pin. A gist of the present invention is a method for manufacturing a wiring board, which includes a step of forming a large-diameter portion.

According to this means, since the solder is welded to the tip of the pin, the large diameter portion can be easily formed. In addition, since the large-diameter portion is solder, it is well wetted by the pin connection solder, so that the large-diameter portion can be reliably connected by the pin connection solder.

Further, in order to achieve the above object, a solution according to a tenth aspect of the present invention resides in that, prior to the step of forming the large-diameter portion by welding the solder, a pin adjacent to the large-diameter portion at the tip of the pin is formed. The gist of the present invention is a method of manufacturing a wiring board according to claim 9, further comprising a step of forming a solder non-wetting surface on the peripheral surface.

According to this means, before the solder is welded to the tip of the pin, the solder non-wetting surface is formed on the peripheral surface of the pin on the side of the adjacent wiring board body. Therefore, when the solder is welded to the tip of the pin. In addition, it is possible to prevent the solder from spreading to the wiring board body side (root side). Therefore, the shape of the large diameter portion can be made constant.

Further, in order to achieve the above-mentioned object, a solution according to claim 11 is a method of forming a large-diameter portion of a pin adjacent to a large-diameter portion of the pin before the step of welding the solder to form the large-diameter portion. The gist of the present invention is a method of manufacturing a wiring board according to claim 9, further comprising a step of forming a solder non-wetting material on the peripheral surface.

According to this means, the solder non-wetting material is formed on the adjacent pin peripheral surface of the wiring board body before the solder is welded to the pin tip, so that when the solder is welded to the pin tip. In addition, it is possible to prevent the solder from spreading to the wiring board body side (root side). Therefore, the shape of the large diameter portion can be made constant.

Further, in order to achieve the above object, a solution according to claim 12 is to provide a pin body having a flange at or near the tip before the step of welding the solder to form a large diameter portion. The method of manufacturing a wiring board according to claim 9, further comprising a step of projecting the main board from the main surface of the wiring board body.

According to this means, prior to welding the solder to the tip of the pin, the pin body having a flange at or near the tip is protruded from the wiring board body, so that the solder is welded to the tip of the pin. When forming the large-diameter portion, it is possible to prevent the solder from spreading to the wiring board body side (root side). Therefore, the shape of the large diameter portion can be made constant. Further, since it is sufficient that the pin main body having the flange is protruded from the wiring board main body, such a wiring board can be easily formed.

According to another aspect of the present invention, there is provided a wiring board body having at least one main surface and a pin connection solder protruding from the main surface. A wiring board having a large number of pins having a large diameter portion made of a material that does not melt at the same time, and another wiring board, wherein the pins are formed by abutting the tips of the pins against connection pads formed on the other wiring board. The gist is a method for manufacturing a connection body to be connected using connection solder.

According to this means, the pins having the large-diameter portions are connected by using the pin connection solder while abutting the ends of the pins against the connection pads of the other wiring board. Between them, a force due to the surface tension of the molten solder for pin connection acts. Therefore, it is possible to obtain a self-alignment effect in which the wiring boards are automatically moved relative to each other so that each pin is substantially at the center of each pad. Therefore, even if the positions of the wiring board and the other wiring boards are slightly displaced, the wiring boards are automatically moved to the correct positions, so that there is no need to perform high-accuracy positioning of the two and the connection work can be facilitated.

[0042]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of a wiring board 10 according to a first embodiment. The multilayer wiring board main body 1 is made of alumina ceramic, and a large number of pin fixing pads 3 (860 μm in diameter) made of tungsten are formed on the main surface (lower surface in the figure) 1a. This pad 3 has Ag-
42 alloy (42% Ni-Fe alloy) via Cu eutectic silver braze 8
Pin body 5 is fixedly mounted. This pin body 5
It is a so-called nail head type pin with a total pin length of 3.0.
mm, the pin diameter is 0.3 mm, and the head diameter is 0.45 mm.
Also, a high-temperature solder ball 6 (98Pb-2Sn, melting point 322) having a diameter of about 890 μm
° C) is welded to form a pin 7 having a large diameter portion at the tip. A nickel oxide exposed surface (solder non-wetting surface) 5i, which is oxidized so as not to wet the solder, is provided 0.8 mm above the tip (lower end) of the pin body 5 around the pin body 5 in the axial direction. It is formed over 1.0 mm.

On the other hand, near the center of the back surface (upper surface in the figure) 1b of the multilayer wiring board main body 1, a large number of chip connection pads 9 (125 μm in diameter) made of molybdenum for connecting an integrated circuit chip 11 to be described later. It is formed in a lattice shape. The chip connection pads 9 and the pin fixing pads 3 are connected to each other by wiring (not shown) in the multilayer wiring board main body 1. As described later, nickel plating and gold plating are applied to the surface of the pin body 5 on the side of the multilayer wiring board body 1 from the pad 3, the silver solder 8, and the solder non-wetting surface 5a. The surface of the chip connection pad 9 is also plated with nickel and gold.

Then, as shown in FIG. 2, the chip pads 13 of the integrated circuit chip 11 and the chip connection pads 9 of the multilayer wiring board main body 1 are connected to a high-temperature solder (90 Pb-10Sn, melting point 3).
(01 ° C.) 15 for flip-chip connection. In addition,
At this time, the chip ball 13 and the chip connection pad 9 are connected by selecting a temperature at which the high-temperature solder ball 6 does not melt.

Thereafter, the wiring board 10 is connected to the printed wiring board 20. The printed wiring board 20 has a printed wiring board main body 21 made of a glass-epoxy resin composite material (JIS: FR-4), and a tip end of the pin 7 on a connection surface 21a (upper surface in the drawing) of the printed wiring board main body 21. Cu connection pad (720 μm diameter) 23 for abutting connection
Are formed at positions corresponding to the pin fixing pad 3 and the pin 7, respectively. On the connection pad 23, a Pb-Sn eutectic solder paste (37Pb-63Sn, melting point 1
83 ° C.) 25 are each applied by screen printing.

After the wiring boards 10 are aligned and superimposed so that the high-temperature solder balls 6 are respectively positioned on the connection pads 23, the wiring boards 10 are put into an infrared reflow furnace at a maximum temperature of 220 ° C., and the solder paste 25 is melted. As shown in FIG.
The high-temperature solder balls 6 formed at the tips of the pins 7 and the connection pads 23 are connected by eutectic solder 26. At this time,
The molten eutectic solder 26 wets the space between the high-temperature solder ball 6 and the pad 23 and generates a force in a direction in which the surface area is reduced as much as possible by the surface tension.

If any of the high-temperature solder balls 6 (accordingly, the axis of the pin main body 5) is located at a position deviated from the center of the pad 23 in a certain direction, the forces generated by the surface tension overlap, and as a whole, This is a force for moving the wiring board 10. With this force, the wiring board 10 moves, and eventually, the adjustment is automatically performed so that the high-temperature solder ball 6 (pin body 5) is located substantially at the center of each connection pad 23.
That is, even if the mutual position between the wiring board 10 and the printed wiring board 20 is slightly shifted before the connection (solder melting), the position is automatically adjusted by the self-alignment effect. Rough positioning allowing deviation is sufficient.

In the above example, the diameter of the high-temperature solder ball 6 (the diameter of the large diameter portion at the tip of the pin) was 890 μm, which was 1.24 times the diameter (720 μm) of the connection pad 23. Since the self-alignment effect is caused by the surface tension of the molten solder for pin connection, when the diameter of the large-diameter portion and the diameter of the connection pad are almost the same, the rate of change in the surface area increases even with a slight deviation. Therefore, the force for correcting the position works greatly. Conversely, when either one is small, the rate of change of the surface area is small, and it is considered that the working force is small. That is, for example, the diameter 7 of the connection pad 23
The diameter of the large diameter portion is set to 500 μm to 1010
When the thickness is set to μm (the range of 0.7 to 1.4 times the pad diameter), a sufficient self-alignment effect can be obtained.

The coefficient of thermal expansion of the multilayer wiring board body 1 made of alumina ceramic used in this example is about 8 × 1.
0 ^-6, glass - thermal expansion coefficient of the printed circuit board body 21 made of an epoxy resin composite material (transverse direction) is approximately 15 ×
10 ^-6 . Therefore, when these are exposed to a high or low temperature, a thermal expansion difference occurs between the two. In such a case, since the pin body 5 is bent to absorb the difference in thermal expansion, the generation of stress is suppressed, and the connection reliability between the two wiring boards is high. Moreover, compared to the connection area between the pin body 105 and the solder 126 when the pin body 105 is directly soldered to the pad 123 (conventional example, see FIG. 8).
Since the connection area between the high-temperature solder ball 6 and the eutectic solder 26 is large, the connection is made stronger. Further, in this example,
A high-temperature solder ball 6 is used for the large diameter portion. This high temperature solder ball 6
Has high affinity with the eutectic solder 26, and when the eutectic solder 26 is melted, a part of the surface of the high-temperature solder ball 6 is melted, so that the two can be connected more firmly and the connection reliability is improved. It can be further improved.

Next, a method for manufacturing the wiring board 10 of this embodiment will be described with reference to FIG. FIG.
FIG. 9 is an explanatory diagram for describing a manufacturing process near the pin 7 in the wiring board 10 shown in FIG. First, a 42-alloy pin body 5 molded into a nail head shape is prepared (FIG. 4).
(a)). An electroless nickel plating layer 3f (1.2 μm thick) is previously formed on the pin fixing pad 3 of the multilayer wiring board main body 1, and the pin main body 5 is formed on the pin fixing pad 3.
Is brazed with an Ag-Cu eutectic silver braze 8 (FIG. 4 (b)).
Then, an electroless nickel plating layer 5 g (2.5 μm thick) was formed on the pin body 5, the silver solder 8, and the pad fixing pad 3.
n) (FIG. 4 (c)).

Thereafter, a plating resist R is applied in the circumferential direction of the pin at a position (upper side in the figure) 0.8 mm below the tip of the pin body 5 and dried (FIG. 4D). Further, the electroless gold plating layers 5h, 5h '(thickness: 0.1 to 0.5 [mu] m)
Is formed, and the plating resist R is removed (FIG. 4E). Then, an exposed portion S is formed in which the underlying nickel plating layer 5g is exposed only in the portion where the resist R was present. Next, the multilayer wiring board main body 1 is put into an atmosphere furnace at a temperature of 450 ° C. for 5 minutes. Then, the portions covered with the gold plating layers 5h and 5h 'are protected by the gold plating layers 5h and 5h'.
g is thermally oxidized to form a nickel oxide layer 5i (FIG. 4).
(f)). The nickel oxide layer 5i is stable and does not wet with solder. Further, since the nickel oxide layer is oxidized by the heat treatment, the nickel oxide layer can be surely formed, and the nickel oxide layer has little change such as peeling, so that the solder can be stably and reliably repelled.

Next, for example, a high-temperature solder paste (98Pb-2S) is disposed on a non-wetting plate B made of alumina ceramic having heat resistance and not wettable by solder in a position corresponding to each pin body 5.
n) Apply 6a. On top of that, the multilayer wiring board main body 1 is positioned so that the front end of the pin main body 5 corresponds, and the front end of the pin main body 5 is brought into contact with the paste 6a (FIG. 4).
(g)). Thereafter, the high-temperature solder paste 6a is put into a 360 ° C. reflow furnace to melt the high-temperature solder paste 6a, thereby forming a high-temperature solder ball 6 at the tip of the pin body 5 (FIG. 4 (h)). At this time, since the nickel oxide layer 5i does not wet with the molten high-temperature solder, the high-temperature solder does not flow toward the pin root side (the multilayer wiring board main body 1 side), but has a substantially spherical shape at the tip. Since the gold plating layer 5h 'at the tip is eroded by the high-temperature solder balls 6 and diffused therein, it is considered that the high-temperature solder balls 6 and the nickel plating layer 5g are directly connected. By doing as described above, the wiring board 10 including the pin 7 having the large-diameter portion formed of the high-temperature solder ball 6 at the tip of the pin main body 5 can be formed. In addition, as the non-wetting plate B, carbon (graphite), stainless steel, or the like can be used in addition to ceramics such as alumina ceramic and silicon nitride.

(Embodiment 2) In Embodiment 1, the nickel oxide layer 5i is formed as a solder non-wetting surface in the middle of the pin body 5, but in this embodiment, the nickel black layer is formed on the exposed portion S. The dyeing treatment liquid is acted on to blacken the nickel in the exposed portion S. Black-dyed nickel layer 5j
Has the property of not getting wet with the molten solder similarly to the nickel oxide layer 5i, so that the high-temperature solder balls 6 can be formed in the same manner as in the first embodiment as shown in FIG. According to this example, a high temperature treatment called thermal oxidation is not required.

Third Embodiment In the first embodiment, the exposed portion S of the nickel plating layer 5g is formed at an intermediate portion of the pin body 5 and thermally oxidized to form the nickel oxide layer 5i. However, in this example, as shown in FIG. 5B, the entire gold plating layer 5 was formed without forming an exposed portion.
Then, an epoxy resin-based solder resist SR is applied in the form of a ring in the middle of the pin and dried, and then a high-temperature solder ball 6 is formed in the same manner as in the first embodiment. Also in this case, the high-temperature solder melted by the solder resist SR is prevented from flowing to the pin root side, so that a high-temperature solder ball 6 having a fixed shape can be formed. The solder resist S
Instead of R, a high-temperature solder ball 6 can be formed similarly by forming a glass layer by applying and firing a glass paste.

(Embodiment 4) In the above-mentioned embodiments 1 to 3, a solder repelling property was formed so that the high-temperature solder did not flow to the pin root side. In this embodiment, FIG.
As shown in the figure, a flange portion 5 bulging in the radial direction near the tip of the pin.
A high-temperature solder ball 6 is formed at the tip of the pin by using the pin body 5 ′ having s. In this example, as shown in FIG. 5D, a flange 5s (a flange diameter of 0.45 mm and a thickness of 0.2 mm)
Is formed in advance, and the pin body 5 'is silver-brazed to the pad 3 and nickel-plated and gold-plated as in the first embodiment. However, unlike the first embodiment, the exposed portion S is not formed with the resist R or the exposed portion S is not thermally oxidized. As shown in FIG. 5 (d), the tip of the pin body 5 ′ is positioned on the high-temperature solder paste 6a applied on the non-wetting plate B, and as shown in FIG. 5 (e).
The tip of the pin body 5 'is brought into contact with the paste 6a.

The high-temperature solder paste 6a is melted as it is, and the high-temperature solder is welded to the tip of the pin body 5 '. In this example, the molten high-temperature solder flows toward the pin root because of the flange 5s. (Wet spreading) is prevented. It is considered that the area in contact with the high-temperature solder is increased by the flange portion 5s, so that the surface tension suppresses the spread of wetness. Thus, the high-temperature solder ball 6 can be formed at the tip of the pin body 5 '(FIG. 5).
(c)). In the present embodiment, it is not necessary to perform a process for each pin body such as thermal oxidation or resist coating, and it is sufficient to form a pin body having such a shape in advance, so that the pin body can be easily formed.

(Embodiment 5) In Embodiment 4 described above, a pin body 5 'having a flange 5s near the front end is used. In this embodiment, the flange 5s whose front end bulges in the radial direction is used. The constituent pin body 5 'is used. That is, in this example, a pin body 5 'having a tip end shaped like a nail head is used. The high-temperature solder balls 6 may be formed with the high-temperature solder paste 6a applied on the non-wetting plate B as in the fourth embodiment.
As shown in FIG. 5 (f), a flange 5s at the tip of the pin body 5 '
The high-temperature solder ball 6 'is adhered with a solder flux not shown in FIG.
An example of welding on the tip side of s is shown. As a result, FIG.
As in (c) (except for the broken line), the high-temperature solder ball 6 can be formed at the tip of the pin body 5 '.

(Embodiment 6) In the above embodiments 1 to 5, the high temperature solder balls 6 are formed at the tips of the pin bodies 5 and 5 ', and the large diameter portion is provided at the tip of the pin. In the present embodiment, as shown in FIG. 5 (g), a pin body 5 "having a spherical tip 5t at the tip itself is used. After the plating, nickel plating and gold plating are performed, except that the exposed portion S is not formed with the resist R or the exposed portion S is thermally oxidized unlike the first embodiment. Also, the formation of the sphere 6 is not performed, so that steps such as application of the resist R, thermal oxidation, and application and melting of the high-temperature solder paste 6a are not required, and are the same as those in the manufacture of the conventional PGA type wiring board. Therefore, it is possible to manufacture the wiring board of the present embodiment without using any new facilities or processes, and to provide an inexpensive wiring board. Because the cell is formed The alignment effect can be obtained, and the connection area with the solder for pin connection increases, so that the connection strength can be improved.The shape of the pin tip is spherical (FIG. 5 (g)). In addition, a hemisphere (FIG. 5 (h)), a columnar shape (FIG. 5 (i)), or the like can be appropriately selected and used.

(Embodiment 7) In the above embodiment, an example in which the integrated circuit chip 11 is mounted on the upper surface 1b of the wiring board 1 has been described. In addition, semiconductor elements such as transistors, capacitors, resistors and the like are mounted. You can also. Further, as shown in FIG. 6, a relay wiring board (relay board) 7 interposed between a printed circuit board 60 and a printed circuit board (upper circuit board) 41 on which electronic components such as an integrated circuit chip 51 are mounted.
The present invention may be applied to 0. Relay board 70 of this embodiment
In the embodiment, a pin 77 is connected to a lower surface 71a of a wiring board main body (relay board main body) 71 via a pin fixing pad 73 as in the first embodiment. An upper wiring connection pad 79 for connecting to the wiring board 41 is formed on the upper surface 71b, and the pin fixing pad 73 and the pad 79 are connected by a via or an internal wiring (not shown).

The wiring substrate 41 has an integrated circuit chip 51 mounted thereon by flip-chip connection via a chip pad 49 formed on the upper surface 41b.
In 1a, a relay board connection pad 43 is formed at a position corresponding to the upper wiring board connection pad 79 of the relay board main body 71. The pad 43 for connecting the relay board and the pad 79 for connecting the upper wiring board are connected to a high-temperature solder (95Pb-5).
Sn) 45. The printed wiring board 60 is the same as that used in the first embodiment, and includes a connection pad 63 formed on the upper surface 61a and a high-temperature solder ball 76 forming a large diameter portion at the tip of the pin 77. Are connected by eutectic solder 66.

For example, the printed wiring board main body 61 is made of a material having a relatively large coefficient of thermal expansion such as a glass-epoxy resin composite material, and the wiring board 41 is made of a material such as ceramics having a relatively small coefficient of thermal expansion such as alumina. In this case, if both are connected directly via solder, a difference in thermal expansion occurs due to a temperature change. For this reason, when heating and cooling are repeated, a problem such as breakage of the solder may occur. In such a case, the relay board 70 using the relay board main body 71 made of the same material as the wiring board 41 (a material having a similar coefficient of thermal expansion)
Interposed between them, there is almost no difference in thermal expansion between the wiring board 41 and the relay board main body 71, and the difference in thermal expansion between the relay board main body 71 and the printed wiring board main body 61 is It is absorbed by the deformation of the pin 77. Therefore, the wiring board 41 and the printed wiring board 60 can be connected with high reliability. That is, when the present invention is applied to a relay board, a high reliability is obtained by interposing the relay board between two wiring boards having different coefficients of thermal expansion.
Connection between two wiring boards.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a wiring board of the present invention.

FIG. 2 is an explanatory diagram showing a state in which a wiring board of the present invention to which an integrated circuit chip is connected is connected to another wiring board.

FIG. 3 is an explanatory view showing a state in which a wiring board of the present invention to which an integrated circuit chip is connected is connected to another wiring board;

FIG. 4 is an explanatory diagram illustrating a manufacturing process of a portion near a pin in the wiring board according to the first embodiment;

FIG. 5 is an explanatory diagram illustrating a pin state and a manufacturing method of a wiring board according to Examples 2 to 6;

FIG. 6 is an explanatory diagram showing a state where a wiring board on which an integrated circuit chip is mounted and a printed board are connected using the wiring board of the present invention as a relay board according to the seventh embodiment.

FIG. 7 is an explanatory view showing how a conventional butt joint PGA type wiring board is connected to another wiring board.

FIG. 8 is an explanatory view showing a state in which a conventional butt joint PGA type wiring board is connected to another wiring board.

FIG. 9 is an explanatory view showing a state in which a conventional butt joint PGA type wiring board is connected to another wiring board in a shifted state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Multilayer wiring board main body 3 Pin fixing pad 5, 5 ', 5 "pin main body 6 High-temperature solder ball (large diameter part) 5t Large diameter part 7 pin 8 Silver solder 9 Chip connection pad 10 Wiring board 11 Integrated circuit chip 13 Chip pad 20 Printed wiring board 21 Printed wiring board main body 23 Connection pad 26 Pin connection solder (eutectic solder)

Claims (13)

[Claims] 1. A wiring board main body having at least one main surface and a number of pins projecting from the main surface, and the tips of the pins abut against connection pads formed on another wiring substrate. A wiring board for connecting to another wiring board by soldering while using a pin connection solder, wherein the pin has a large diameter made of a material that does not melt at the tip thereof when the pin connection solder is soldered. A wiring board, comprising a part. 2. The wiring board according to claim 1, wherein the large-diameter portion is made of solder having a melting point higher than that of the pin connection solder. 3. The wiring board according to claim 2, wherein a solder flow preventing portion is formed adjacent to a large-diameter portion at the tip of the pin. 4. The wiring board according to claim 3, wherein, as the solder flow preventing portion, a pin peripheral surface adjacent to a large-diameter portion at the tip of the pin serves as a solder non-wetting surface. 5. The wiring board according to claim 3, wherein the solder flow preventing portion is formed by forming a solder non-wetting material on a peripheral surface of the pin adjacent to a large diameter portion at the tip of the pin. 6. The wiring board according to claim 3, further comprising a flange portion made of a material of a pin body, adjacent to the large diameter portion at the tip of the pin, as the solder flow preventing portion. 7. The wiring board according to claim 1, wherein the pin is a pin whose tip has a large diameter. 8. The maximum diameter of the large diameter portion of the pin is set to be 0.7 to 1.4 times the diameter of a connection pad formed on the another wiring board for connection with the pin. The wiring board according to any one of claims 1 to 7, wherein 9. A wiring board body having at least one main surface and a number of pins protruding from the main surface, the diameter of which is made of a material that does not melt when soldering a pin connection solder to a tip of the pin. A method of manufacturing a wiring board comprising a large part, comprising a step of forming a large diameter part at the tip of the pin by welding a solder having a higher melting point than the solder for pin connection. Production method. 10. The method according to claim 1, further comprising, before the step of forming the large diameter portion by welding the solder, forming a solder non-wetting surface on a peripheral surface of the pin adjacent to the large diameter portion at the tip of the pin. The method for manufacturing a wiring board according to claim 9. 11. A method for forming a non-wetting material on a peripheral surface of a pin adjacent to a large-diameter portion at the tip of the pin before the step of forming a large-diameter portion by welding the solder. The method for manufacturing a wiring board according to claim 9. 12. The method according to claim 12, further comprising, before the step of forming the large-diameter portion by welding the solder, a step of projecting a pin body having a flange at or near the tip from the main surface of the wiring board body. The method for manufacturing a wiring board according to claim 9. 13. A wiring board body having at least one main surface, and a plurality of pins protruding from the main surface and having a large-diameter portion made of a material that does not melt at the end of the wiring substrate when soldering the pin connection solder. Wiring board and other wiring board,
A method of manufacturing a connector, wherein the pins are connected by using the pin connection solder while abutting the tips of the pins against connection pads formed on the other wiring board.