JP2538542B2 - Electrical connection device - Google Patents

Description

Description: (1) Technical Field The present invention relates to an electrical connection device, and more specifically, for example, a relatively large number of separable interconnections can be provided with a zero insertion force and a zero extraction force in a relatively small space. A connection device, particularly an LSI module, an IC module, which can be performed in a state close to
The present invention relates to a device for electrically connecting electrical devices such as a circuit board, that is, a connector.

(2) Background of technology In recent years, the density of integrated circuits has increased, and especially when connecting an LSI module to a circuit board, connection is made by several thousand connecting points. It is desirable to easily connect and disconnect such a large number of connection points.

FIG. 1 is an explanatory view showing a connection state between an LSI module and a printed circuit board, which is a typical one for connecting an electric device having a large number of connection points.

(11) is an LSI chip, and (12), (13), and (14) are large-scale integrated circuit LSI modules. (18) is a printed circuit board, (15) is a place where the fourth LSI module is to be mounted, (16) is a through hole for a guide pin opened in the printed circuit board (18), and (17) is Circuit pattern pads on the surface of the printed circuit board (18), and (19) are printed contacts for contact with contacts such as a card edge connector. LSI module (12), (1
When 3) and (14) become highly integrated, several thousand pads or terminals are attached to the bottom surface or side surface of an LSI module or the like, and these pads or terminals are attached to the printed circuit board (1
8) Need to connect to.

(3) Conventional Technology and Problems Conventional electrical connection devices are usually composed of pins (contact pins) corresponding to male contacts and jacks corresponding to female contacts. It is designed to get mutual connection. The jack is provided with a spring mechanism capable of applying a considerably strong contact force to the contact pin in order to ensure stability of contact with the contact pin. However, since this spring mechanism works and a considerable amount of contact force is applied to all contact pins, the insertion force when inserting the contact pins into the jack or the removal force when removing the contact pins from the jack can be ignored. It grows to the extent it does not. Actually, the contact pin insertion force and the withdrawal force increase as the number of contact pins per unit connecting device increases, and when the number of contact pins is on the order of several hundreds, it is several tens kg or more. Insertion force is required. In this case, it is no longer possible to manually operate the connecting device, and it is necessary to insert and remove the pin using jigs.

Further, in the conventional connecting device as described above, when a large pin insertion force and withdrawal force are applied when attaching and detaching the connecting device, the electric device is often undesirably damaged. Furthermore, in such a connecting device, it is necessary to give strength to the constituent members thereof that can withstand a large pin insertion force and withdrawal force,
As a result, the size of the device itself must be increased.

Recently, attempts have been made to reduce the pin insertion force and the withdrawal force by coping with the increase in the number of pins per connecting device. For example, they are known as zero insertion force (ZIF) connection devices and light insertion force (LIF) connection devices. There is a connecting device that applies contact force with a cam mechanism after inserting the contact pins into the jack, or a connecting device that adopts a mechanism for dividing and connecting with a slide cam instead of connecting all at once, and others. That is it. However,
These connecting devices require a complicated mechanism and complicated handling associated therewith, and also cause an increase in manufacturing cost.

An electrical connecting device for connecting a conventional LSI module to a circuit board is generally composed of contact pins protruding from the bottom surface of each LSI module and a jack door of a circuit board into which the contact pins can be inserted. Further, the jack on the circuit board is provided with a spring mechanism having a certain shape for applying a contact force having a considerably large strength to the contact pin. However, when such a connecting device is used, as in the case of the connecting device as described above, a larger pin insertion force is required as the number of contact pins of the module increases, and a practical operation becomes impossible. .

In addition, this type of connecting device requires a considerably larger space than expected because the jack is provided with a spring mechanism having a certain shape. Such an increase in space is generally a factor that limits the number of contact pins that can be provided in a module or the like, which makes it impossible to obtain an electrical connection device having high density contact pins.

(4) Object of the Invention The object of the present invention is to provide an improved electrical connection device that overcomes the above-mentioned drawbacks, in other words, it can be easily assembled and disassembled with very small pin insertion and removal forces. Yes, high quality multi-contact connection is possible, and a large number of electrically independent contacts can be connected at high density in a relatively small space, and the cost required for assembly is low, and the reliability is high. The object is to provide an entirely new type of electrical connection device that provides high electrical interconnection.

(5) Structure of the Invention The above object of the present invention is a device for electrically connecting two electric devices, which comprises a connection board made of a rigid insulator interposed between these devices. The substrate has a high melting point metal contact member for electrically connecting with the device, and has a low melting point metal for fusing with the contact member of the device on the contact surface of the contact member, and To achieve by an electrical connecting device characterized in that a resistance heating element is embedded in the insulator in the vicinity of the low melting point metal in a state of being insulated from the metal and in the vicinity of the contact point member of the high melting point metal. You can

In the electrical connecting device of the present invention, when two electric devices having circuit patterns to be connected to each other have conductive pads protruding above the conductive via holes as contact members, positions corresponding to these pads are provided. In, the connection board has a conductive via hole penetrating in the thickness direction,
It is preferable that the via hole has a conductive pad projecting from both main surfaces of the connection substrate as a contact member, and the low melting point metal is arranged on the pad.

In addition, it has a circuit pattern to be connected to each other.
In the case where one of the two electric devices has a contact pin as a contact member and the other device has a conductive pad protruding above the conductive via hole as a contact member, at positions corresponding to these contact members, The connection board has a hole for inserting the connection pin, which is recessed in the thickness direction of the board to a thickness of about half, and a conductive via hole penetrating the remaining thickness, and the via hole is the hole. It is preferable to have conductive pads protruding on the bottom surface of the substrate and on the main surface of the substrate opposite to the hole, and the low melting point metal is arranged on these pads.

 Ceramic is convenient as an insulator for forming the connection board.

 The insulator may also be plastic.

 A solder alloy may be used as the low melting point alloy.

The resistance heating element can be formed as a thin film or a thick film as in a conventional method.

 Hereinafter, the present invention will be described in detail.

When the present invention is carried out, a ceramic material such as alumina, forsterite, or mullite as an insulating material of a connection board, or a glass ceramic material which is a composite material of glass such as borosilicate glass and ceramic such as alumina, or The machinable ceramic material (Makor; trade name of Corning Incorporated, USA), and a photosensitive glass ceramic material such as Photoserum (trade name of Corning Incorporated) can be advantageously used.
Depending on the case, when it is necessary to process holes such as holes and embed heating elements, or to facilitate manufacturing, a resin material with heat resistance,
For example, polybutadiene, polyimide, and other materials can be used instead of the ceramic material.

When the device is operated under normal conditions in the present invention, useful low melting point metals preferably have a melting point of 100-170 ° C. Such metals include solder alloys such as
In-Sn alloy, Bi-Sn alloy, Bi-Pb alloy, Rose alloy (S
n, Bi, Pb), and others can be advantageously used. When the melting point of the low melting point metal is 100 ° C. or lower, the metal may be melted during the operation of the electric device, which may cause a connection failure. This is because, when the device is used in a normal state, the temperature of the module mounting the element rises due to the heat generation of the LSI element, and further the temperature of the connection board adjacent thereto also rises. On the other hand, when the melting point of the low melting point metal is excessively high, it is necessary to raise the temperature for melting the low melting point metal, and accordingly, the temperature of the connection substrate containing the low melting point metal also inevitably rises. This adversely affects the printed circuit board arranged in the vicinity of the connection board. That is, the circuit on the printed circuit board is
Normally, a 60Sn-40Pb solder plating film is formed, and the melting point of this solder material is approximately 180 ° C. Therefore, if the temperature of the connection board exceeds this temperature, the solder plating film may be thermally affected. sell. Further, even if the printed circuit board is made of a material such as polyimide having excellent heat resistance, it is inevitable that the printed circuit board is also thermally affected. For the above reason, the preferable melting point range of the low melting point metal according to the present invention is defined as described above. However, the range of this melting point is currently
It is specified for the device used under normal conditions. For example, when the module, circuit board, etc. are cooled with immersion liquid, or the thermal constraint conditions for the printed circuit board and solder plating film are changed. If so, the preferred melting point range of the low melting point metal is not limited to the range described above. Further, since the melting point of the metal is within the above range, it is advantageous from the viewpoint of the heating element used in combination therewith.

In the present invention, a heating element for melting the low melting point metal is essential. The heating element is not particularly limited as long as it does not adversely affect the connection device of the present invention and effectively guides heating of the connection substrate and melting of the low melting point metal. As an example, use thick film and thin film resistors to wire it inside the connection board, or use thick film and thin film resistors to form it on the surface of the connection board, and then use an insulating layer. It can be covered or used as a heating element. Nichrome or the like is generally used as the resistance material, but it is not particularly limited. The latter configuration is advantageous when it is intended to reduce the number of steps, and in that case, as long as it is arranged in the vicinity of the low-melting point metal, the shape and number of heating elements to be formed,
Position etc. is not a problem at all.

If necessary, a metal layer for a heat sink can be formed near the low melting point metal. The formation of such a metal layer is effective in concentrating the heat from the heating element around the low melting point metal without conducting the heat evenly to the periphery thereof, thus enhancing the melting efficiency. It is understood that the shape of the metal layer is not limited, but it is advantageous to form the metal layer so as to surround the low melting point metal. A metal material useful for forming such a metal layer is, for example,
Au, Ag, Cu and others. When a conventional method such as a thick film forming method, a sputtering method, or a vacuum vapor deposition method is applied using such a metal material, a target metal layer can be technically easily formed.

In order to perform the contact point connection, the electrical connection member of the electric device to be connected is aligned with the connection position of the connection board so as to face the low melting point metal and adjacent to the high melting point metal of the contact member. First, the connection board is heated by passing an electric current through the resistance heating element, and then the low melting point metal at the connection position is melted by the heat transfer effect. In this state, the connected electric device, for example, the module is lightly pressed. In that state, the power supply to the heating element is cut off, the temperature of the connection substrate is lowered, and the low melting point metal is solidified. In this way, a reliable, low contact resistance connection can be obtained.

When the contact connection is released, the connection substrate can be heated by energizing the heating element to melt the low melting point metal, and then the contact connection can be released with a very weak force as in the case of connection.

It is advantageous to previously form the low melting point metal layer on the pads of the contact members of the electric device to be connected by the electric connection board of the present invention, such as the LSI module and the printed circuit board. In this case, the low melting point metal on the pad of the connecting substrate can be melted by the heat generation of the connecting substrate, and at the same time, the low melting point metal of the electric device to be connected can be melted.

(6) Examples Example 1 FIG. 2 shows a connection board (2) which is an embodiment of the present invention.
FIG. 3 is an enlarged cross-sectional view of one via hole in (0) and a portion to be a pad thereof. In FIG. 2, (21) is a slope made of glass ceramic which is an electrical insulator, and (2)
2) is a via hole made of gold conductor, (23),
(24) is a pad portion connected to the via hole (22), (27) is a heating element wired inside the glass ceramic plate (21) in an insulated state from the via hole (22),
(26) is a terminal of the heating element for energizing the heating element (27),
(28) and (29) are low melting point metals for connecting to the pads of the LSI module and the pads of the printed circuit board, respectively. The heating element (27) is wired in a state that it is completely enclosed inside the glass ceramic plate. In this embodiment, a thick film resistor paste (area resistance 100 Ω / sq resistor paste No. 4720 manufactured by DuPont) is used. used. Low melting point metal (2
8) and (29) used an In-48% Sn eutectic alloy (melting point = 117 ° C).

FIG. 3 is a schematic cross-sectional view showing the configuration when a large number of pads are connected when the LSI module and the printed circuit board are connected using the connection board of the present invention. In FIG. 3, (12) is an LSI module similar to that shown in FIG.
An LSI chip is attached to the SI module. (31) is L
A pad on the bottom of the SI module that is attached to connect to the pad on the connection board. (32) is a low melting point metal, and (33) is a guide pin for positioning when connecting and assembling with a connection board and a printed circuit board. The printed circuit board (18) is a multilayer circuit board,
(41) is an insulator such as resin, and (42), (43) and (44) are copper foils constituting a circuit, and each layer is completely independent by the insulator (41). Each copper foil layer (42), (4
The circuits 3) and (44) are connected to the pad (17) which is the circuit pattern on the surface by the through hole plating layer (45). (46) is a low melting point metal for connecting to the pad portion of the connection substrate (20), and the same In-48% as (28) and (29)
(47) which uses Sn eutectic alloy is a guide hole for positioning when connecting. The hole (39) of the connection board (20) is also a guide hole for positioning.

In this embodiment, for example, the LSI module (12) is provided with the pads (31) arranged in a square area of 40 × 40 mm with a total spacing of 1.27 mm and a total of 900 pads insulated from each other. Also, this LSI module (12) pad (3
Pads (23), (24), and (17) are aligned and provided on the front and back of the connection board corresponding to 1) and on the position of the printed circuit board. The number of these 900 pads is very large,
It is also understandable that the connection has a high density.

The LSI module (12) and the printed circuit board (1
8) and the connection board (20) via the connection board, the connection board (20) is aligned and placed on the printed circuit board (18), and the LSI module (1
2) Align and stack, apply a load of 600g on it,
In this state, the heating element (27) is energized to melt the low melting point metal (28), (29), (32), (46) of each pad portion,
Turn off the power when both low melting point metals are integrated,
The low melting point metal is solidified as it is. With this procedure LS
A stable electrical connection between the I module and the printed circuit board was obtained via the connection board. At this time, the contact resistance of each pad portion was 1 mΩ or less.

The connection between the LSI module (12) and the printed circuit board (18) can be released by performing the reverse process of the connection.

Embodiment 2 FIG. 4 shows a connecting board (2) which is another embodiment of the present invention.
It is an enlarged sectional view of a portion which is one connection point of 0 ').
In FIG. 4, (21) is a plate made of an electrically insulating glass ceramic, (22) is a via hole made of a gold conductor, (23) and (24) are via holes ( The pad part, which is connected to 22), (25) is a glass-ceramic (21) to pool the low melting point metal (30).
(66) is a chamfered portion of the hole, (27) is a heating element wired inside the glass ceramic plate (21) in an insulated state from the via hole and the hole, and (26) is a heating element. Terminal of heating element for energizing (27), (29), (30)
Is a low melting point metal. The heating element (27) is wired in a state that it is completely enclosed inside the glass ceramic plate. In this embodiment, a thick film resistor paste (area resistance 100 Ω / sq resistor paste No. 4720 manufactured by DuPont) is used. used. Low melting point metals (29) and (30) are In-48% Sn eutectic alloys (melting point = 11
7 ° C) was used.

FIG. 5 is a schematic cross-sectional view showing the structure when a large number of pads and connecting pins are connected when connecting an LSI module and a printed circuit board using the connecting board of the present invention. In FIG. 5, (12 ') is an LSI module similar to that of FIG. 1, and an LSI chip is attached to this LSI module. Reference numeral (67) is a connection pin provided on the bottom surface of the LSI module, which is provided so as to be inserted and connected in the hole of the connection board. (33) is a guide pin for positioning when connecting and assembling with the connection board and the printed circuit board. The printed circuit board (18) is a multilayer circuit board,
(51) is an insulator such as resin, (52), (53) and (54) are copper foils constituting a circuit, and each layer is completely independent by the insulator (51). Each copper foil layer (52), (5
The circuits 3) and (54) are connected to the pad (17) which is the circuit pattern on the surface by the through hole plating layer (55). (56) is a low melting point metal for connecting to the pad portion of the connection board, and the same In-48% Sn eutectic alloy as (29) and (30) is used. (57) is a guide hole for positioning when connecting. The hole (39) of the connection board (20 ') is also a guide hole for positioning.

In this embodiment, for example, in the LSI module (12 ′), the electrical connection pins (67) are 1.27 in a square area of 40 × 40 mm.
A total of 900 pieces are arranged in an insulated state at intervals of mm. Also, this LSI module (12 ')
Holes (25) and via holes (22) for pooling the low melting point metal at the position of the connection board corresponding to the connection pins of
Pads (23) and (24) are provided, and the pads (2
A pad (17) is provided at a position of the printed circuit board (18) corresponding to 3). LSI module (12 ') in Fig. 5
The procedure for connecting the printed circuit board (18) and the printed circuit board (18) via the connection board (20 ') is to position the connection board (20') on the printed circuit board (18) in an aligned manner, Position the connection pin (67) on the bottom of the LSI module (12 ') in the hole of the and align it so that it is lightly inserted. Furthermore, add a load of 600 g on the LSI module,
In this state, the heating element (27) is energized to melt the low melting point metal (29), (30), (56) in the pad portion and the hole portion,
The low melting point metal (29) and (56) in the pad part are integrated, and the low melting point metal (30) in the hole part and the connection pin (67) are wet. Solidify. By this procedure, stable electrical connection between the LSI module and the printed circuit board was obtained via the connection board. At this time, the contact resistance of each connection part was 1 mΩ or less.

The connection between the LSI module (12 ') and the printed circuit board (18) may be released by performing the reverse process of the connection.

(7) Effects of the Invention In the electrical connecting device of the present invention, the force required for connecting and disconnecting the contacts is smaller as it is closer to no load, and even if the number of contacts is in the order of thousands. It is substantially equivalent to the unloaded state. Furthermore, since the portion of the conventional connecting device that corresponds to the jack is made by melting and solidifying the low-melting-point metal, the spring mechanism attached to the jack is unnecessary, and therefore the space (occupied area) per contact is at most 2 mm. ² and a dramatic reduction. As a result, a large number of contact connection points can be provided in a relatively small area. Also, since such melting and solidification is a kind of diffusion connection, a very stable and low contact resistance is obtained, and the contact is self-maintained only after the connection, and especially means such as external tightening is not required. Does not matter.

[Brief description of drawings]

FIG. 1 is a plan view showing a connection state between an LSI module and a printed circuit board, FIG. 2 is an enlarged sectional view showing a main part of a connection board which is one embodiment of the present invention, and FIG. FIG. 4 is a cross-sectional view showing a connection state of the connection board of FIG. 2, FIG. 4 is an enlarged cross-sectional view showing a main part of a connection board which is another embodiment of the present invention, and FIG. FIG. 6 is a cross-sectional view showing a connection state of the connection board of FIG. 12, 12 ', 13, 14 ... LSI module, 17 ... Printed circuit board pad, 18 ... Printed circuit board, 20, 20'
...... Connecting board, 21 ...... Connecting board insulator, 22 ...... Connecting board via hole, 23, 24 ...... Connecting board pad, 25 ...
… Connection board hole, 27 …… Connection board resistance heating element, 28, 2
9、30 …… Low melting point metal for connection board, 31 …… LSI module pad, 32 …… Low melting point metal for LSI module, 33 ……
Guide pin, 39,47,57 …… Guide hole, 67 …… Connecting pin,
46, 56 …… Low melting point metal for printed circuit boards.

Continuation of front page (56) References JP 54-116670 (JP, A) JP 50-9339 (JP, B1)

Claims (7)

(57) [Claims] 1. A device for electrically connecting two electrical devices, comprising a connecting substrate made of a rigid insulator interposed between the devices, the substrate electrically connecting to the device. It has a high melting point metal contact member for connection,
A contact member of a high melting point metal having a low melting point metal for fusion bonding with the contact point member of the device on the contact surface of the contact point member, and being insulated from the metal in the vicinity of the low melting point metal. A resistance heating element is embedded in the insulator in close proximity to the electrical connection device. 2. When two electric devices having circuit patterns to be connected to each other have conductive pads protruding above the conductive via holes as contact members, the connecting substrate has a thickness at positions corresponding to these pads. Characterized in that it has a conductive via hole penetrating in a direction, the via hole has a conductive pad protruding on both main surfaces of the connection substrate as a contact member, and a low melting point metal is arranged on this pad. The electrical connection device according to claim 1. 3. Two electric devices having circuit patterns to be connected to each other, one of which has a contact pin as a contact member, and the other device has a conductive pad protruding above the conductive via hole. When it is used as a contact member, at a position corresponding to these contact members, the connection board penetrates through a hole into which the connection pin is inserted, the hole being recessed to a thickness of about half, and the remaining thickness. A conductive via hole, which has a conductive pad protruding on the bottom surface of the hole and on the main surface of the substrate opposite to the hole, and the low melting point metal is arranged on these pads. The electrical connection device according to claim 1, characterized in that. 4. The device according to claim 1, wherein the insulator forming the connection board is ceramic. 5. The device according to any one of claims 1 to 3, wherein the insulator forming the connection substrate is plastic. 6. A device according to any one of claims 1 to 5, wherein the low melting point metal is a solder alloy. 7. The device according to claim 1, wherein the resistance heating element is a thin film or thick film resistance element.