JPS58184278A - Method of mounting pin - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, pins are temporarily identified on a pin fixing board in advance, and then one end of the pin is arranged.

This relates to a method of attaching pins to the wiring board by sewing and attaching the pins to the pin connection pattern of the wiring board and then melting the solder or wax that has been supplied in advance. .

^Circuit modules for computers, communication devices, etc., which require consideration of density, are increasingly using ceramic substrates from the viewpoints of compactness, reliability, and cost reduction.

These circuit modules have the L8 chip and other components mounted on one or both sides of a multi-node ceramic substrate, and use the surface where components are not mounted to input/output signals, power, etc. The input/output pins are installed.

If the integration level of the module is low, the number of input/output pins may be small, and the pins may be attached to the side of the board, or the density of the internal F- and surface patterns of the board may be small, so through-holes may be installed in the board. Methods such as fixing by passing a pin through the through hole have been used.

However, as the number of input/output pins became thicker and the wiring density on the board surface 6 increased as modules became more densely concealed, the number of input/output pins increased, and the wiring density on the board surface 6 increased. It has become impossible to make holes and attach bottles.

For this reason, it is illegal to form a pin pattern on the surface of the board and solder or braze the pin against this pattern. ,■ is included in bottle 4! A method called ``method'' has come to be used for shitsuke.

These modules are usually not used alone, but are electrically connected to other modules or other components. As for the connection body, printed wiring boards mainly made of resin components such as epoxy resin and phenol resin are mainstream, and the module mounting provided on these printed boards is done through the through-holes of the circuit module. is inserted, solder etc. are applied, and the printed board and module are connected via the through holes and vias. However, module l1111 Cerami-5.

The coefficient of thermal expansion of printed circuit boards is α5 to α7×1010, while the coefficient of thermal expansion of substrates used for printed wiring is 2 to 4
It has a coefficient of thermal expansion of 10-51°0, and there is a large difference between the two.

This difference is caused by the fact that when a thermal cycle is applied after a module is soldered to a printed wiring board, a large strain is generated between the printed wiring board and the ceramic board, and the thermal stress generated by this strain is the weakest in terms of strength. This has led to serious drawbacks such as cracks occurring at the connection between the ceramic substrate and the bottle, causing the connection to break over time.The purpose of the present invention is to eliminate the above-mentioned drawbacks and reduce thermal stress at the connection between the bottle and the ceramic substrate. The purpose of the present invention is to provide a method for attaching a bottle in a manner that prevents the generation of stress and other stresses. A bottle is temporarily fixed to a substrate, and one end of the bottle is fixed by soldering or brazing to the bottle connection pattern provided on the IC on the ceramic substrate, and the stress generated by external force acting on the tip of the bottle is fixed with a pin. The purpose is to prevent stress from being absorbed by the substrate and generated at the connection between the bottle and the ceramic substrate.

An embodiment of the present invention is shown in Figures #11 to #! This will be explained with reference to Figure 8.

Fig. 1 is a cross-sectional view showing a method for temporarily fixing a bottle to a pin fixing board, in which 1 is a bottle, 2 is a pin fixing board, 5 is a through hole with a metallized layer applied inside, and pads 4 and 5 on both sides. Hole, 6 is ring solder, 7 is bottle position rt
This is a holder for holding the sweat rack and pin fixing board 2, and has an alignment hole 8 at the position where the bottle is placed.

Figure 2 shows the bottle 1t pin/physical board 2! It is a cross-sectional view showing a state temporarily fixed with solder, where 9 indicates a solder fillet, and other symbols indicate the same contents as in Figure @1.

FIG. 3 is a sectional view showing a state in which the bottle is soldered to a ceramic substrate, where 10 is a ceramic substrate, 11 is a connection pattern for connecting the blinded bottle 1 on the ceramic substrate, and 12 is a ceramic substrate. , nine solder fillets are formed on the side of the substrate 10. The inside and surface of the ceramic substrate 10 have many circuit patterns for forming circuits, but these are omitted in the figure.

Also in FIG. 3, other symbols have the same contents as those shown in FIG. 1.

With this table structure, the method of temporarily fixing the bottle will be explained first with reference to FIG. 1. The pin fixing board 2 is installed on the upper surface of the holder 7.

This pin fixed substrate 2 is made of the same material and under the same formation conditions as the ceramic substrate 10 in order to match the coefficient of thermal expansion with the ceramic substrate 10.

By aligning the holder 7 and the pin fixing board 2 with alignment marks (not shown) provided on each, the position sewing hole 8 of the holder 7 and the through hole of the pin fixing board 2 are aligned. The centers of hole 5 coincide. In this state, the bottle 1 is inserted into the through hole S from above the in-circuit board 2.

As a result, the lower end of the bottle 1 comes into contact with the bottom surface of the alignment hole 8 of the holder 7, and the solder ring 6 is supplied to the primary pin 1 where the position of B/1 is set. For the composition of the solder ring 6, we used Sm10-Pb solder, which is a high-melting solder for printed board solders, to prevent it from melting when the module is soldered to the printed board, but other compositions or 8m- Low melting point solder such as Au type solder, ring solder using Makumu gsOu solder etc. can also be applied.
Next, apply 7x to pin 1, ring solder 6, and pad 4 (flux is not shown), and apply 350'O
Pass through a N2 atmosphere furnace with a peak temperature of .

There are many other heating methods, such as using a heating plate, using an infrared lamp, and blowing hot air, but any method can be used. As shown, the ring solder is completely melted and the pin 1 and through hole 3 are completely joined by the solder.
A portion of the solder .:1 forms a solder fillet 9 on the pad 5.

Next, attach pin 1 to pin fixing board 2 as shown in Figure 2. .

In the temporarily fixed state, the bottom of the pin 1 is connected to the bottle connection pattern 1 of the ceramic substrate 10 coated with flux.
1, the ceramic substrate 10 and the bottle fixing substrate 2 are positioned to have a certain dimension between them, and heat treatment is performed again under the same conditions as the temporary fixation. As shown in FIG. 3, the pin 1 lands on the connection pattern 11 of the ceramic board 10, forming a solder fillet 12 to complete a complete solder joint. The shape of′
In order to ensure that the distance between the bottle fixing substrate 2 and the ceramic substrate 10 is a certain distance, as shown in FIG.
By forming one end of the through hole 3 in a tapered shape, the bottle fixing substrate 2 and the ceramic substrate 10 are brought close together. The overall height of the module can be kept down by 1 degree, and the bottle fixing board 2 and cellar t
The connecting portions of the fixed board 10 are integrated, allowing for a more complete connection. The solder necessary to connect the bottle fixing substrate 2 and the ceramic substrate 10 in FIGS. 3 and 4 is all the solder that was supplied when temporarily fixing the pin 1 to the bottle fixing substrate 2, and the solder shown in FIG. The size of the ring solder 6 shown in
This is determined by calculating the amount of solder required for both of these connections.

FIG. 5 is a sectional view showing another embodiment of the present invention. Since the bottle fixing substrate 2 and the ceramic substrate 10 are made of materials with the same coefficient of thermal expansion, the displacement of the connection part between the ceramic substrate 10 and the pin 1 is small.

Moreover, since the stress generated in the connection part is small, the tip of the pin can be made thinner, and the connection pattern 11 can be made smaller. 13 can be formed, and it is possible to improve the edge density variation.

Figures 6 to 8 are diagrams for explaining the effects of the present invention. Figure 6 is a diagram in which the ceramic substrate 10 is soldered to the printed wiring board 11C using the conventional method. When the cycle is applied, pin 1 is released as shown in Figure 7.
produces distortion as shown by the dotted line, and this distortion
5°, which is a major cause of connection breakage.

On the other hand, as shown in FIG. 8, by providing the bottle fixing board 2 according to the present invention, all the strain is absorbed at the lower end of the bottle fixing board 2, and no strain is transmitted to the connection part. As a result, the occurrence of cracks in the connection can be completely prevented.

As described above, according to the present invention, thermal stress due to thermal cycles after the module is affixed to the printed wiring board does not occur at the connection between the pins and the ceramic board, and the mounting of the pins is prevented. Since the thermal stress generated in the joint during heating and cooling can be made very small, the reliability of the joint can be greatly improved.

In addition, the pins can be attached to the connection pattern of the ceramic board after precisely aligning the flatness of the ends of the pins.Furthermore, since the pins are aligned on the bottle fixing board, subsequent It is very easy to sweat in the position when you are in the position.

Furthermore, when handling the module after the bin W4fr, it is very easy to handle the bin since the bin is completely mechanically protected by the bin fixing board. Furthermore, it is possible to employ a much narrower perspiration pattern than the conventional pin contact 8-s, and the wiring density on the ceramic substrate can be greatly improved.

Furthermore, since the stress at the connection part can be reduced, it becomes possible to attach a large number of bins to a large-area board.1 This expands the possibilities of ultra-high-density, large-area hybrid modules and greatly increases production efficiency. can be improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a method of temporarily fixing a bottle according to the present invention;
Figure 2 is a cross-sectional view after the bottle is temporarily fixed, Figure 5183 is a cross-sectional view showing the bottle soldered to the ceramic substrate,
1-m1i, Figure 5 is a cross-sectional view showing another embodiment of the present invention, Figures 6 and 7 are cross-sectional views of a module soldered to a printed board by the conventional method, and Figures iJ & 8 are according to the present invention. FIG. 1 is a sectional view of a module mounted on a printed board. 1...Bin 2...Bin fixing board 3...Through hole 6...Solder ring 7...Holder 10... ... Ceramic board 11 ... Connection pattern 14 ... Printed wiring board 15, 15' ... Crack (,,, 1st m o 2 I 3I! 1 4th a 5th Prisoner Off M O 8 Otsu

Claims (1)

[Claims] In the method of attaching input/output pins to wiring boards using ceramics, etc., pins with a metalized layer that can be soldered or brazed to pin fixing boards with a coefficient of thermal expansion equal to or similar to that of the board are used. Insert a pin into the insertion hole, solder or braze the cough bottle and the metallized layer, and make sure that the pin connection position on the wiring board and the end face position and position of the pin installed on the pin fixing board are the same. The bottle mounting method is characterized in that the pins are attached to the wiring board by soldering or brazing by sewing the pins to the wiring board and heating the pins.