JPH0158836B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to electrical connection devices, and particularly to electrical connection devices, particularly for making a large number of separable interconnections within a relatively small area with very little insertion and removal forces. The present invention relates to a connecting device, that is, a connector, which can provide a stable and reliable connection even after being inserted and removed many times.

(b) Prior art and problems Conventional electrical connection devices usually consist of a pin (contact pin) corresponding to a male contact and a jack corresponding to a female contact, and through their fitting, the electrical device They are designed to connect with each other. The jack is equipped with a spring mechanism capable of applying a significant contact force to the contact pin to ensure stability of contact with the contact pin. However, this spring mechanism works and a fairly strong contact force is applied to all the contact pins, so the insertion force when inserting the contact pin into the jack or the removal force when removing the contact pin from the jack is less than the unit connection. The larger the number of contact pins per device, the larger the insertion force, and when the number of contact pins is on the order of several hundred, an insertion force of tens of kilograms or more is required. In this case, it is no longer possible to operate the connecting device by input, and it is essential to insert and remove pins using jigs.

Furthermore, in the conventional connection devices as described above, when a large pin insertion force and removal force is applied during attachment and detachment, electrical devices are often damaged. Furthermore, in such a connecting device, it is necessary to provide its constituent members with sufficient strength to withstand large pin insertion and removal forces, and as a result, the device itself is forced to increase in size.

Recently, attempts have been made to reduce the pin insertion and removal forces in response to the increase in the number of pins per connection device. For example, they are known as zero insertion force (ZIF) and light insertion force (LIF) connections. There are connection devices that use a cam mechanism to apply contact force after the contact pin is inserted into the jack, or connection devices that use a slide cam to connect in parts rather than all at once, and others. That's it. However, these connection devices require complicated mechanisms and
This requires complicated handling and also causes an increase in manufacturing costs.

Conventional electrical connection devices for connecting LSI modules to circuit boards generally consist of contact pins protruding from the bottom of each LSI module and a circuit board jack into which the contact pins can be inserted. Additionally, the jack of the circuit board is provided with a spring mechanism of some configuration for applying a fairly strong contact force to the contact pins. However, when using such a connection device, as in the case of the connection device described above,
As the number of contact pins in the module increases, a larger pin insertion force is required, making practical operation impossible.

This type of connection also requires a considerable amount of space for the spring mechanism of the jack. This increased space is generally a limiting factor in the number of contact pins that can be provided on a module etc.
It is not possible to obtain an electrical connection device with a high density of contact pins.

The present inventor has previously proposed a new type of electrical connection device that overcomes the above-mentioned drawbacks of conventional electrical connection devices in Japanese Patent Application No. 57-51155. The electrical connection device according to the invention includes a connection board made of an insulating material, a guide hole drilled through the connection board into which a contact pin of an electrical device can be inserted, and a metal formed in a part of the guide hole. It comprises a reservoir, a low melting point metal housed in the metal reservoir and used for connection between contacts, and a heating element disposed near the metal reservoir for melting the low melting point metal. It is characterized by

That is, the electrical connection device of the invention penetrates the connection board and connects the connection board to the position corresponding to the contact pins, wiring patterns, etc. of the electrical device to be connected, on the connection board made of an insulating material. A pore is drilled into which a pin can be inserted, and a metal reservoir is provided anywhere inside this pore to pool a low melting point metal (used for connection between contacts of electrical equipment). The desired contact connection is achieved by melting and solidifying the low melting point metal pooled in the reservoir by operating an attached heating element.

FIG. 1 shows one embodiment of the connection device of the invention.
FIG. 2 is an enlarged cross-sectional view of a portion that becomes two connection points. The connection board 1 shown in the figure is made of alumina, which is an electrical insulator, with a
A guide hole 2 is bored into which a contact pin (not shown) is inserted. Both ends of the guide hole 2 are chamfered, as indicated by 2', to allow smooth insertion of the contact pin. In the center of hole 2,
A metal reservoir 3 is formed, and a low melting point metal 4 is pooled in the metal reservoir 3. A heating element 5 is formed around the metal reservoir 3 so as to surround it. 6 is a terminal for supplying electricity to the heating element.

FIG. 2 is a partially enlarged cross-sectional view showing two electrical devices (not shown) connected via their respective contact pins using the connecting device according to the invention shown in FIG. . The contact pins are designated 11 and 12 and are fixedly supported by insulating contact pin supports 13 and 14, respectively. The tips of the contact pins 11 and 12 are buried in the solidified low melting point metal 4 that completely fills the metal reservoir 3. Contact pin supports 13 and 1
4, stoppers 15 and 16 for positioning the contact pins are formed at several locations (only one location is illustrated in FIG. 2). A member 17 provided through the connecting device 10 and the contact pin supports 13 and 14 is a pin for lateral positioning when connecting these members. Figure 3 also shows an LSI with many contact pins.
FIG. 4 is an enlarged sectional view of one connection point of another embodiment of the connection device of the invention for connecting a module and a printed circuit board, and FIG. 4 shows a connection made by this embodiment. FIG. 3 is a schematic cross-sectional view showing the configuration at that time. The shape of this device is basically the same as that shown in FIG. 1, except that the metal reservoir 3 has been moved to the lower end of the guide hole 2 and its shape has become funnel-like. LSI module 21 has contact pin 31
is 1.27 [mm] within a given area, for example 40 x 40 [mm].
They are installed at intervals of 900 in total. These contact pins are each insulated and have annular pads 36 as shown. The annular pad 36 is fused to the bottom surface of the LSI module. Guide holes 2 are provided in the connection board 1 to correspond to the contact pins arranged in alignment on this LSI module, and circuit patterns 25 of the printed circuit board 20 are provided at positions corresponding to these guide holes. and 28 are arranged in line.

Printed circuit board 20 is a multilayer printed circuit board. Reference numerals 29 in the figure represent copper foils constituting the circuit, and each of them is completely independent due to the insulating material of the substrate 20. Each copper foil layer 29 is connected to the circuit patterns 25 and 28 on the substrate surface by a through-hole plating layer 34 and a plating layer 35.

In this way, a large number of contact pins 31, guide holes 2, and circuit patterns 25 and 28 are connected to the stopper 3 attached to the LSI module 21.
The position is determined by the guide pins 33 with two guide holes 7 of the connection board 1 and the guide holes 26 of the printed circuit board 20.

As explained above, the invention of the prior application provides an electrical connection device that can perform electrical connection and disconnection with very little insertion force and removal force. However, in the electrical connection device of the prior invention, a part of the low melting point metal melted when the contact pins are inserted and removed is, for example, the lower part of the circuit pattern 25 which is the connected part of the printed circuit board 20 in FIG. There is a phenomenon in which water flows down into the through-hole section. For this reason, as the contact pin is repeatedly inserted and removed, the amount of low-melting point metal inside the metal reservoir gradually decreases, and the number of times that a stable connection can be achieved is limited, and an improvement is desired.

(c) Purpose of the Invention The purpose of the present invention is to enable electrical connections and disconnections to be made with very small pin insertion and removal forces, and to allow a larger number of pins to be connected in a relatively small space. It is an object of the present invention to provide an electrical connection device that can connect electrically independent contacts with high density and that can provide stable connection even when inserted and removed many times.

(d) Structure of the Invention The object of the present invention is to provide a connection board made of an insulating material, a first contact pin having one end buried in the connection board, and a first contact pin formed in the connection board. a metal reservoir from which the metal reservoir is exposed, a guide hole for a second contact pin that is bored in the connection board and reaches the metal reservoir, and a guide hole for the first contact pin and the second contact pin that are accommodated in the metal reservoir. This is achieved by an electrical connection device comprising a low melting point metal used for connection and a heating element disposed near the metal reservoir to melt the low melting point metal.

That is, the electrical connection device of the present invention, like the device according to the prior invention described above, uses the low melting point metal pooled in the metal reservoir provided in the connection board by operating the attached heating element. The desired contact connection is achieved by melting and solidifying, but
In the prior invention, the metal reservoir has two openings formed by the contact pin guide hole penetrating the connection board, whereas in the present invention, one of the contact pins connected by the low melting point metal has two openings. It is embedded in the connection board in advance, and the opening of the metal reservoir is one guide hole on the side of the second contact pin inserted from the outside. Therefore, when the low melting point metal is melted and the contact pin is inserted or removed, the flow of the molten metal from the metal reservoir is suppressed, and a stable connection can be obtained even after many insertions and removals.

In order to make a connection using the electrical connection device according to the present invention, it is necessary to insert the device into one of the electrical devices to be connected, such as a printed circuit board, by means of soldering by inserting an embedded contact pin. The contact pins of the other electrical device to be connected are aligned facing each other at the connection position of the connection board, and the connection board is first connected by passing a current through a heating element placed near the metal reservoir. The low melting point metal in the metal reservoir is melted by the heat transfer effect, and in this state, the electrical device to be connected, such as a module, is lightly pressed and its contact pin is inserted into the connection board, leaving the pin inserted. In this state, the power to the heating element is cut off, the temperature of the connection board is lowered, and the low melting point metal in the metal reservoir is solidified. In this way, a reliable, low contact resistance connection can be obtained.

When disconnecting the contact, the connection board is heated by energizing the heating element as in the case of connection, and the contact pin is removed after the low melting point metal is melted.
In this way, the contact connection can be broken with very low force.

(e) Embodiments of the Invention The present invention will be specifically explained below using embodiments with reference to the drawings.

FIG. 5 is a sectional view showing an embodiment of the electrical connection device according to the present invention. In the figure, 41 is a first connection board, 42 is a second connection board, 43 is an embedded contact pin, 44 is a guide hole that also serves as a metal reservoir,
45 is a low melting point metal, 46 is a heating element, 47 is an adhesive layer, and 48 is a metal layer.

In this example, the connection boards are 41 and 42.
The area of the first connection board 41 is approximately 40 mm x 40 mm, and the thickness of the first connection board 41 is approximately 1 mm. [mm], and the thickness of the second connection board 42 is approximately 2 [mm].

The first connection board 41 is provided with 30×30=900 guide holes 44 having a diameter of about 0.6 mm and serving as metal reservoirs at a pitch of 1.27 mm. The guide hole 44 can be formed by conventional techniques such as laser processing, electron beam processing, and ultrasonic processing, but the material used in this embodiment can also be formed by drilling.

A heating element 46 is provided on one side of this first connection board 41.
form. FIG. 6 shows a plan view of the pattern of the heating element 46 in this embodiment. As the pattern of the heating element 46 shown in FIG. 6, the heating element 46 (resistor) and the conductor 49 connecting them are formed using a thick film screen technique. In the illustrated example, the dimensions of the heating element were 0.4 [mm] in width and 1 [mm] in length.

Since there are 30 guide holes 44 per row in the longitudinal direction, 30 heating elements as shown are formed and a conductor is formed to connect them in series. These heating elements connected in series have 30 holes, so 31 in the horizontal direction of the figure.
form a line. Next, the resistors in each column are connected in parallel using conductors. In this example, resistance paste No. 4720 manufactured by EI DuPont was used as the heating element, and No. 9770 conductive paste manufactured by the same company was used as the conductor. Of course, other heating elements and conductive pastes may be used, and thin film techniques such as sputtering may also be applied. The resistance measured between the positive and negative electrodes of the heating element thus manufactured was approximately 250 [Ω].

The second connection board 42 also has a diameter of approximately 0.4 mm.
After providing a [mm] through hole in the same arrangement as the first connection board 41, a hole with a depth of approximately
Enlarge the hole diameter to 0.5 [mm] and to approximately 0.6 [mm] in diameter. Next, a part of the metal layer 48 is formed on the inner wall of this hole by a thick film method. The above diameter is about 0.6
The shape of the bottom of the [mm] hole is preferably flat, but it may be an inclined surface.

Thereafter, as shown in FIG. 5, the first connection board 41 and the second connection board 42 are bonded together using an adhesive layer 47. In this example, 9137 paste manufactured by EI DuPont is used as the adhesive.

Next, connect the embedded contact pins 43 to the second connection board 42.
, and the gap between the two is filled with gold-tin (Au-Sn) alloy paste and fixed.

The embedded contact pin 43 of this embodiment has a diameter of approximately
Approximately 0.6 [mm] in diameter with a brim of approximately 0.5 [mm] in height.
A 0.3 mm phosphor bronze pin plated with palladium (Pd).

Next, an appropriate amount of the low melting point metal 45 is pooled in the guide hole 44, which also serves as a metal reservoir.

When operating the apparatus of the present invention under normal conditions, useful low melting point metals are preferably 100 to 170°C.
It has a melting point of Examples of such metals include In-Sn alloy, Bi-Sn alloy, Bi-Pb alloy,
Rose alloys (consisting of Sn, Bi, Pb), etc. can be advantageously used. The melting point of low melting point metal is
If the temperature is below 100 degrees Celsius, this metal may melt during operation of the electrical device, causing a connection failure. This is because when the device is used under normal conditions, the heat generated by the LSI element causes the temperature of the module on which the element is mounted to rise, and the temperature of the adjacent connection board to rise as well. on the other hand,
If the melting point of the low melting point metal is too high, it is necessary to increase the temperature for melting it, which inevitably increases the temperature of the connection board containing the low melting point metal. This has an adverse effect on printed circuit boards placed in the vicinity of the connection board. In other words, circuits on printed circuit boards are usually formed with a 67Sn-40Pb solder film, and the melting point of this solder material is approximately 180.
[°C], so if the temperature of the connection board exceeds this temperature, the solder-plated film may be thermally affected. Furthermore, even if the printed circuit board is made of a material such as polyimide that has excellent heat resistance, it is inevitable that the printed circuit board will also be affected by heat. For the above reasons, the preferable melting point range of the low melting point metal according to the present invention is defined as described above. However, this melting point range is currently specified for equipment used under normal conditions, and for example where modules, circuit boards, etc. are immersion liquid cooled, or where printed circuit boards and If the thermal constraints on the solder-plated film are changed, the preferred melting point range of the low melting point metal is not limited to the range stated above.

Note that the Au-Sn alloy used for fixing the embedded contact pin 43 mentioned above to the second connection board 42 has a melting point of 280 [°C] and is higher than the low melting point metal 4.
This does not melt during the melting of 5. Therefore, when the low melting point metal 45 is melted to connect or disconnect the contact pin of the electrical device to be connected, the embedded contact pin 43 side is sealed to prevent the low melting point metal 45 from flowing out. be done.

(f) Effects of the Invention As explained above, the electrical connection device of the present invention can connect and disconnect electrical devices with very little insertion and removal force, and has a relatively small area. It is possible to provide a stable and highly reliable connection by suppressing the loss of low-melting point metal even after multiple insertions and withdrawals without losing the effect of being able to provide a very large number of connections within the connector. can.

[Brief explanation of drawings]

FIG. 1 is a partially enlarged cross-sectional view showing an example of a conventional electrical connection device, FIG. 2 is a cross-sectional view showing a state in which contact pins are connected using the conventional example, and FIG.
The figure is a partially enlarged cross-sectional view showing a connection between an LSI module and a printed circuit board using another conventional example; FIG. 4 is a cross-sectional view showing a connection configuration using the conventional example; FIG. 5 is a partially enlarged sectional view showing an embodiment of the present invention, and FIG. 6 is a plan view showing a heating element pattern of the embodiment. In the figure, 41 and 42 are connection boards, 43
4 is a buried contact pin, 44 is a guide hole which also serves as a metal reservoir, 45 is a low melting point metal, 46 is a heating element, 47 is an adhesive layer, 48 is a metal layer, and 49 is a conductor.

Claims (1)

[Scope of Claims] 1. A ceramic material having guide holes for contact pins, thick film resistance heating elements formed by baking on both sides of each guide hole on one surface, and the heating elements connected by a thick film conductor. a first connection board made of aluminum, and a through hole in which two holes having the same diameter as the guide hole and a diameter smaller than the guide hole are coaxially formed in two stages,
a second connection board made of ceramic that is disposed in the same manner as the guide hole and has a thick metal layer deposited on the inner wall of the through hole; and a second connection board that is fitted into the through hole of the second connection board. an embedded contact pin having a flange, and the heating element mounting surface of the first connection board and the opening surface of the large diameter hole of the second connection board are insulated so that the centers of the holes coincide with each other. and the collar portion of the embedded contact pin fits into a large diameter hole of the second connection board;
An electrical connection device in which the tip of the pin is inserted into the hole with a small diameter so as to protrude, the pin is sealed and baked to the metal layer on the inner wall of the through hole with a metal paste, and a low melting point metal is accommodated in the guide hole.