JP2020126765A - Transmission cable connection structure, transmission cable module, and transmission cable connection method - Google Patents

Abstract

To reduce an amount of heat transfer to a cable by melting a solder in a short time to achieve a solder connection for a low heat resistance transmission cable with a simple configuration.SOLUTION: A transmission cable connection structure of solder-connecting a wiring of a circuit substrate and a conductor of a signal transmission cable is so configured that an exothermic material having a self-propagating high temperature synthesis reaction is formed near the wiring of the circuit substrate, a solder paste is placed on the wiring of the circuit substrate, and the wiring of the circuit substrate is connected to the conductor of a signal transmission cable by melting the solder paste using reaction heat when the exothermic material is subjected to a self-propagating high temperature synthesis reaction due to external excitation.SELECTED DRAWING: Figure 2C

Description

The present invention relates to a transmission cable connection technique that enables large-capacity signal transmission in information communication equipment.

In recent years, in data centers, the amount of data processed by the device has increased and the transmission speed inside the device has become faster, so that 100 Gbps/lane level transmission is required. In such 100 Gbps/lane class transmission, it is predicted that transmission on the board will be the limit even for short distances, and the needs for on-board cable transmission will increase. In addition, high flexibility is desired in order to improve the degree of freedom in routing the transmission cable within the device. These transmission cables are generally used by being soldered to a circuit board or an electrical connector in order to obtain an electrical connection.

Known conventional connection structures for transmission cables include JP2003-243110A (Patent Document 1) and JP2013-239270A (Patent Document 2).

Patent Document 1 describes a method of solder-connecting a coaxial cable and a circuit board via a concave connection jig. This enables electrical connection, prevents short circuit failures, and improves signal transmission quality.

Further, Patent Document 2 describes a method in which a connection tape is wound around a shield exposed at the end of a cable to draw out a wire to be a terminal for soldering, and the connection tape and a circuit board are connected by soldering. This enables electrical connection, prevents deformation and melting of the insulator (dielectric) during solder connection work, and prevents deterioration of transmission characteristics.

JP, 2003-243110, A JP, 2013-239270, A

As an example of a structure in which a transmission cable has high flexibility, in a cable in which a material of an insulator (dielectric) is changed, there is a possibility that heat resistance may be deteriorated by changing the material, for example, using polyethylene. Therefore, it is desired to suppress deformation and melting of the insulator (dielectric) due to heat during solder connection with a simple structure.

In each of the structures disclosed in Patent Document 1 and Patent Document 2 described above, the solder connection between the transmission cable and the circuit board is performed via additional components such as a connection jig and a connection tape. Therefore, the manufacturing cost may increase. In addition, if overheating for solder connection is performed for a long time, there is a possibility that deformation or melting of the insulator (dielectric) cannot be suppressed.

In order to solve the above-mentioned problems, the present invention has a simple structure and reduces the amount of heat transferred to a cable by performing solder melting in a short time, and realizes solder connection of a transmission cable with low heat resistance. Has an aim.

In order to achieve the above-mentioned object, the present invention connects a transmission cable and a circuit board by melting the solder by utilizing the reaction heat of self-propagating high-temperature synthesis (SHS). It is a thing.

To give an example of the "transmission cable connection structure" of the present invention,
A transmission cable connection structure in which wiring of a circuit board and a conductor of a signal transmission cable are solder-connected, wherein a heat-generating material having a self-propagating high-temperature synthesis reaction is formed near the wiring of the circuit board, and on the wiring of the circuit board. Solder paste is arranged, by melting the solder paste by utilizing the reaction heat when the heat-generating material self-propagating high temperature synthesis reaction by external excitation, the wiring of the circuit board and the conductor of the signal transmission cable Is connected.

Moreover, if an example of the "transmission cable connection method" of the present invention is given,
A transmission cable connecting method for connecting a conductor of a signal transmission cable to wiring of a circuit board by soldering, wherein a heat-generating material having a self-propagating high-temperature synthesis reaction is formed near the wiring of the circuit board, and on the wiring of the circuit board. Arranging a solder paste, causing a self-propagating high-temperature synthesis reaction of the heat generating material by external excitation, melting the solder paste by the generated reaction heat, and connecting the wiring of the circuit board and the conductor of the transmission cable Is.

According to the present invention, it is possible to realize solder connection of a transmission cable having low heat resistance with a simple structure.

FIG. 3 is a perspective view showing a connection form of the transmission cable of the first embodiment. It is a perspective view showing an example of a transmission cable. 3 is a schematic diagram illustrating a transmission cable connection structure and a connection process (initial state) of Example 1. FIG. 5 is a schematic diagram illustrating a transmission cable connection structure and a connection process (during solder supply) of Example 1. FIG. 3 is a schematic diagram illustrating a transmission cable connection structure and a connection process (during solder connection) of Example 1. FIG. FIG. 5 is a schematic diagram illustrating a modified example of the transmission cable connection structure of the first embodiment. FIG. 5 is a schematic diagram illustrating a transmission cable connection structure and a connection process (initial state) of a second embodiment. FIG. 6 is a schematic diagram illustrating a transmission cable connection structure and a connection process (during solder supply) of a second embodiment. 7 is a schematic diagram illustrating a transmission cable connection structure and a connection process (during solder connection) of Example 2. FIG. It is a schematic diagram explaining the transmission cable connection structure of Example 3, and a connection process (initial state). FIG. 9 is a schematic diagram illustrating a transmission cable connection structure and a connection process (during solder supply) of a third embodiment. FIG. 6 is a schematic diagram illustrating a transmission cable connection structure and a connection process (during solder connection) of a third embodiment. It is a schematic diagram explaining the transmission cable module of Example 4.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In all the drawings for explaining the embodiments, the elements having substantially the same functions are designated by the same names and reference numerals, and the repeated description thereof will be omitted.

Example 1 of the present invention will be described with reference to FIGS. 1A to 2C. 1A and 1B are perspective views showing an example of the transmission cable connection configuration and the configuration of the transmission cable of the first embodiment. 2A to 2C are schematic diagrams illustrating the transmission cable connection structure and connection process of the first embodiment.

First, the transmission cable connection configuration and the configuration of the transmission cable according to the first embodiment will be described with reference to FIGS. 1A and 1B. In FIG. 1A, for simplification, illustration of a solder resist and a solder on a circuit board, which will be described later, is omitted.

As an example of the present invention, description will be given using an example in which the transmission cable 1 is soldered to the circuit board 2. In FIG. 1A, a plurality of wirings 210 for transmitting a high-speed signal are arranged on the circuit board 2, and the wirings 210 and the conductors 140 of the plurality of transmission cables 1 are soldered to each other for electrical connection. It is configured to get.

In the configuration of the transmission cable 1, as shown in FIG. 1B, a conductor 140 is covered with a dielectric 130, and an outer peripheral portion thereof is covered with a GND shield 120 made of a conductor. Further, the outside is covered with an insulating jacket 110.
Here, the conductor 140 is made of a copper alloy wire. The material of the dielectric 130 is fluororesin or the like, and its film thickness is a thickness that satisfies the standard of the characteristic impedance of the transmission line. The GND shield 120 is made of copper plating or the like. The material of the insulating jacket 110 is vinyl chloride resin, polyurethane, fluororesin, or the like, and the film thickness thereof is suitable for the outer diameter of the cable.

In the present embodiment, the twinax cable has been described as an example of the transmission cable, but the transmission cable is not limited to this, and may be a coaxial cable having one conductor for signal transmission. This also applies to other embodiments.

Next, a transmission cable connection structure and a connection process example of the first embodiment will be described with reference to FIGS. 2A to 2C. 2A shows an initial state of the transmission cable connecting portion of the circuit board, (a) is a plan view, and (b) is a sectional view taken along line AA. FIG. 2B shows a sectional view at the time of solder supply. 2C shows a state at the time of solder connection, (a) is a plan view, and (b) is a sectional view taken along line AA.

In the present embodiment, the circuit board 2 in the initial state before connection is characterized in that the solder resist that is usually formed to suppress the spread of the solder at the time of solder connection is self-propagating high temperature synthesis (instead of the solder resist material). SHS: Self-Propagating High-Temperature Synthesis) It is formed by a material system that causes a reaction and that they are integrated. In this embodiment, as a combination of the exothermic material (hereinafter referred to as SHS material) 30 having a self-propagating high temperature synthesis reaction, a material system composed of Si and N that causes a reaction of 3Si+2N ₂ =Si ₃ Ni ₄ is used. Make up thirty. The reason for selecting this material system is that the substance Si ₃ Ni ₄ produced by the SHS reaction exhibits insulating properties. When the product is conductive, the SHS material 30 is integrated, so that the wirings are electrically short-circuited and the signal cannot be transmitted.

First, as shown in FIG. 2A, a solder resist material made of the SHS material 30 is formed so that the transmission cable connection point of the wiring 210 is exposed at the end of the circuit board 2 and around the transmission cable connection point. The solder resist material defines the supply position of the solder paste to be supplied next.

Next, as shown in FIG. 2B, a solder paste 40 serving as a bonding material is supplied onto the wiring 210, which is the opening of the SHS material 30, where solder connection is to be performed on the circuit board 2. In the present embodiment, the solder paste 40 is supplied by screen printing, but it is not necessary to be restricted to this, and vapor deposition solder may be formed in advance or may be supplied by a dispenser. This also applies to other embodiments.

Next, as shown in FIG. 2C, after the solder paste 40 is supplied, the transmission cable 1 is placed at a place where solder connection is to be performed. That is, at the end of the transmission cable 1, the conductor 110 exposed by removing the coating 110 and the dielectric 130 is placed on the solder paste, and then solder connection is performed. Therefore, the reaction of the SHS material 30 formed on the circuit board 2 is started. In this embodiment, laser excitation is used as the external excitation 50. By irradiating a part of the SHS material 30 with laser light, the substances contained in the SHS material 30 (Si, N in this embodiment) start to react. Since this reaction is a self-propagating high-temperature synthesis reaction and the SHS material 30 is integrated, a part of the reaction causes the reaction to propagate to the entire SHS material 30. The propagation speed is very fast, and generally the reaction is completed in 1 second or less, and the exothermic temperature at that time is 1000° C. or more. Therefore, the solder paste 40 is melted with very little external excitation energy and in a short time, and the wiring 210 of the circuit board 2 and the conductor 140 of the transmission cable 1 are solder-connected.

It should be noted that the method of the external excitation 50 does not have to be limited to laser excitation, and any method such as electric spark, voltage application, heating, etc. that initiates self-propagating high temperature synthesis of the substance in the SHS material 30 can be used. The same applies to the examples.

In this embodiment, Si and N are used as the material system that causes the self-propagating high temperature synthesis (SHS reaction). Needless to say, it is not necessary to be regarded as the present material system, and any combination of exothermic materials that cause a self-propagating high-temperature synthesis reaction, and a substance that is insulating can be used. Further, needless to say, the combination of two or more materials is not limited, and any combination of more materials may be used as long as the combination causes a self-propagating high temperature synthesis reaction.

Further, in the present embodiment, as the formation pattern of the SHS material 30, the form in which the solder resist in the vicinity region for solder connection is made of a material system that causes the SHS reaction has been described. This is because the amount of the material system that causes the SHS reaction is suppressed as much as possible and the cost is reduced. However, you don't have to be caught in it. FIG. 3 shows a modification of the transmission cable connection structure of this embodiment. An external excitation application region (pad) 35 is provided in the formation pattern of the SHS material 30 in addition to the vicinity region for solder connection. This facilitates the application of the external excitation 50 and makes it possible to use various external excitation sources.

As described above, according to the connection configuration and the connection process of the transmission cable 1 to the circuit board 2 described in this example, the heat generation (reaction heat) of the heat generation material having the self-propagating high temperature synthesis reaction in the SHS material 30 which is completed in a short time is performed. ), since the solder material is melted, the amount of heat transferred to the dielectric 130 having weak heat resistance can be suppressed, and the solder connection of the transmission cable having low heat resistance can be realized with a simple structure. ..

Second Embodiment A second embodiment of the present invention will be described with reference to FIGS. 4A to 4C. 4A to 4C are schematic diagrams illustrating a transmission cable connection structure and a connection process according to a second embodiment of the present invention.

The second embodiment has a configuration in which the shape of the SHS material 30 of the first embodiment is changed. The second embodiment is different in that the SHS material 30 integrated in the first embodiment is divided so as not to short-circuit each wiring. As shown in FIG. 4A, since the SHS material 30 is divided and formed by the slit 37, even if the substance generated by the SHS reaction has conductivity, each wiring can be electrically short-circuited. Lost. Therefore, the options of the combination (material system) of the SHS material 30 increase. For example, a material system consisting of Ti and C that causes the reaction of Ti+C=TiC, a material system consisting of Ni and Al that causes the reaction of Ni+Al=AlNi, and Zr and H that causes the reaction of Zr+H ₂ =ZrH _2. It is possible to use a material system such as a material system consisting of. This is considered to contribute to cost reduction when the SHS material 30 is formed on the circuit board 2.

Next, as shown in FIG. 4B, the process of supplying the solder paste 40 serving as the bonding material to the portion of the circuit board 2 where the solder connection is to be made is similar to that of the first embodiment.

Next, as shown in FIG. 4C, after the solder paste 40 is supplied, the transmission cable 1 is placed at a place where solder connection is to be performed. That is, at the end of the transmission cable 1, the conductor 110 exposed by removing the coating 110 and the dielectric 130 is placed on the solder paste, and then solder connection is performed. Therefore, the reaction of the SHS material 30 formed on the circuit board 2 is started by the external excitation 50. In the present embodiment, when laser excitation is used as the external excitation 50, unlike the first embodiment, since the SHS material 30 is divided by slits, this laser excitation needs to be performed in multiple times. ..

Therefore, in this embodiment, it is preferable to use an electric spark as the external excitation 50. Since an electric spark is applied to the SHS material 30, it is possible to apply the external excitation 50 to the divided SHS material 30 with one energization by using a fork-shaped electric spark application probe with a branched tip. Becomes

As described above, according to the connection configuration and connection process of the transmission cable 1 to the circuit board 2 described in the present embodiment, in addition to being able to suppress the amount of heat transfer to the dielectric 130 having weak heat resistance, the SHS material 30 Since the wirings are divided so as not to short-circuit, it is possible to increase the selection of material systems that can be used as the SHS material 30.

Example 3 of the present invention will be described with reference to FIGS. 5A to 5C. 5A to 5C are schematic diagrams illustrating a transmission cable connection structure and a connection process according to a third embodiment of the present invention.

The third embodiment is a form in which the formation position of the SHS material 30 of the first embodiment is changed to the back surface of the circuit board 2 (a surface different from the solder connection portion).

In Example 3, the circuit board 2 in the initial state before connection is characterized in that the SHS material 30 formed of a material system that causes an SHS reaction is formed on the back surface of the circuit board 2 (a surface different from the solder connection portion). And that the heat transfer via 230 is formed in the inner layer of the circuit board 2.

As shown in FIG. 5A, in the initial state before solder connection, the circuit board 2 having the heat transfer vias 230 formed in the inner layer of the circuit board 2 is used. Then, the SHS material 30 is formed on the rear surface of the circuit board 2 opposite to the surface on which the wiring 210 is formed so as to be connected to the heat transfer via 230. A solder resist 220 that defines the supply position of the solder paste is provided on the wiring 210.

Next, as shown in FIG. 5B, the process of supplying the solder paste 40 serving as the bonding material to the place where the solder connection of the circuit board 2 is performed is the same as in the first and second embodiments.

Next, as shown in FIG. 5C, after the solder paste 40 is supplied, the transmission cable 1 is placed at a place where solder connection is to be performed. That is, at the end of the transmission cable 1, the conductor 110 exposed by removing the coating 110 and the dielectric 130 is placed on the solder paste, and then solder connection is performed. Therefore, the reaction of the SHS material 30 formed on the back surface of the circuit board 2 is started by the external excitation 50. In this embodiment, laser excitation is used as the external excitation 50. By irradiating the SHS material 30 with laser light, the substances contained in the SHS material 30 start to react. The heat generated by the SHS reaction is transferred to the surface (solder connection surface) of the circuit board 2 via the heat transfer vias 230 formed in the inner layer of the circuit board 2. Therefore, the solder paste 40 is melted and the circuit board 2 and the transmission cable 1 can be connected by soldering with very little external excitation energy and in a short time.

The advantage of this embodiment is that the heat source (SHS material 30) and the solder connection point are separated. As described above, the exothermic temperature of the SHS reaction is generally 1000° C. or higher for a short time. Therefore, a temperature higher than the temperature (energy) required for melting the solder may be applied to the solder connection portion. The structure according to the present embodiment can suppress this excessive temperature (energy) propagation. As a result, it is possible to suppress the amount of heat transferred to the dielectric 130 having low heat resistance.

In this embodiment, as in the second embodiment, the material system for forming the SHS material 30 may, of course, be a combination that causes a self-propagating high-temperature synthesis reaction that includes a substance having conductivity. If the circuit board is thin and has good thermal conductivity, or if the circuit board itself has good thermal conductivity, the heat transfer via 230 may not be provided.

As described above, according to the connection configuration and process of the transmission cable 1 to the circuit board 2 described in this example, it is possible to suppress an excessive amount of heat transfer to the dielectric material 130 having weak heat resistance, and to perform self-propagating high-temperature synthesis reaction. It is also possible to use a material in which the substance produced is electrically conductive, which makes it possible to increase the choice of available material systems.

Example 4 of the present invention will be described with reference to FIG. FIG. 6 is a schematic diagram illustrating a transmission cable module according to the fourth embodiment.

A transmission cable module in which a plurality of transmission cables are connected to an electrical connector is used for electrical connection within a device or between devices. The fourth embodiment uses the transmission cable connection structure of the first to third embodiments for the wiring of the electric connector and the solder connection of the transmission cable.

The electrical connector 6 is provided with a plurality of wirings on the substrate, one end of the substrate is connected to the mating connector, and the other end is provided with a connecting portion for a plurality of transmission cables. As shown in FIG. 6, the transmission cable module is obtained by soldering a plurality of transmission cables 1 shown in FIG. 1B to the connection portion of the electrical connector 6 by using the transmission cable connection structure of Examples 1 to 3.

According to the present embodiment, it is possible to provide a transmission cable module having a simple structure and realizing solder connection of a transmission cable having low heat resistance. In addition, an insulator (dielectric) having low heat resistance can be used for the transmission cable, and the transmission cable can have high flexibility.

1 Transmission Cable 110 Cover 120 GND Shield 130 Dielectric 140 Conductor (Signal Line)
2 Circuit board 210 Wiring 220 Solder resist 230 Heat transfer via 30 Heat generating material having self-propagating high temperature synthesis reaction (SHS material)
35 External Excitation Area (Pat)
37 Slit 40 Solder paste 50 External excitation 6 Electrical connector

Claims (15)

A transmission cable connection structure in which the wiring of the circuit board and the conductor of the signal transmission cable are solder-connected,
An exothermic material having a self-propagating high temperature synthesis reaction is formed near the wiring of the circuit board,
Solder paste is placed on the wiring of the circuit board,
The wiring of the circuit board and the conductor of the signal transmission cable are connected by melting the solder paste by utilizing the reaction heat when the heat generating material undergoes a self-propagating high temperature synthesis reaction by external excitation. Transmission cable connection structure characterized by. The transmission cable connection structure according to claim 1,
The transmission cable connection structure, wherein the heat-generating material having a self-propagating high-temperature synthesis reaction is in the form of a solder resist that defines an arrangement position of the solder paste. The transmission cable connection structure according to claim 2,
A transmission cable connection structure, wherein a region for applying external excitation is formed in a solder resist made of a heat-generating material having a self-propagating high temperature synthesis reaction. The transmission cable connection structure according to any one of claims 1 to 3,
A transmission cable connection structure, wherein the heat-generating material having a self-propagating high-temperature synthesis reaction is a material having an insulating property, which is a compound produced after the self-propagating high-temperature synthesis reaction. The transmission cable connection structure according to claim 4,
A transmission cable connection structure, wherein the material having a self-propagating high-temperature synthesis reaction is composed of Si and N. The transmission cable connection structure according to claim 2,
A transmission cable connection structure, wherein the heat-generating material having a self-propagating high-temperature synthesis reaction in the form of a solder resist is divided so that wirings on a circuit board are not short-circuited. The transmission cable connection structure according to claim 6,
A transmission cable connection structure, wherein the heat-generating material having a self-propagating high-temperature synthesis reaction is composed of Ti and C, or Ni and Al, or Zr and H. The transmission cable connection structure according to claim 1,
On the circuit board, a heat generating material having the self-propagating high temperature synthesis reaction is formed on a surface different from the connection surface between the signal transmission cable and the circuit board,
In the circuit board, a heat generating material having the self-propagating high temperature synthesis reaction, and a heat transfer via for thermally connecting the connection surface between the signal transmission cable and the circuit board,
The heat of reaction when the exothermic material undergoes a self-propagating high-temperature synthesis reaction by external excitation is transferred to the connection surface via the heat transfer via, and the reaction heat is used to melt the solder paste, thereby forming the circuit. A transmission cable connection structure characterized in that the wiring of the substrate and the conductor of the signal transmission cable are connected. A transmission cable module in which conductors of a plurality of signal transmission cables are solder-connected to wiring of an electric connector,
An exothermic material having a self-propagating high temperature synthesis reaction is formed near the wiring of the electrical connector,
Solder paste is placed on the electrical connector wiring,
By melting the solder paste by utilizing the reaction heat when the heat generating material undergoes a self-propagating high temperature synthesis reaction by external excitation, the wiring of the electric connector and the conductor of the signal transmission cable are connected. Characteristic transmission cable module. A transmission cable connecting method for connecting a conductor of a signal transmission cable to a wiring of a circuit board by soldering,
Forming a heat generating material having a self-propagating high temperature synthesis reaction near the wiring of the circuit board;
Place the solder paste on the wiring of the circuit board,
A transmission cable connection method for causing a self-propagating high-temperature synthesis reaction of the exothermic material by external excitation, melting the solder paste by the generated reaction heat, and connecting the wiring of the circuit board and the conductor of the transmission cable. The transmission cable connecting method according to claim 10,
A transmission cable connecting method, wherein the heat-generating material having a self-propagating high-temperature synthesis reaction is formed in the form of a solder resist that defines an arrangement position of the solder paste. The transmission cable connecting method according to claim 11,
A method for connecting a transmission cable, wherein a region for applying an external excitation is formed in a solder resist made of a heat generating material having a self-propagating high temperature synthesis reaction. The transmission cable connecting method according to any one of claims 10 to 12,
The transmission cable connecting method, wherein the exothermic material having a self-propagating high-temperature synthesis reaction is a material in which a compound produced after the self-propagating high-temperature synthesis reaction has an insulating property. The transmission cable connecting method according to claim 11,
A transmission cable connecting method, wherein the heat-generating material having a self-propagating high-temperature synthesis reaction in the form of a solder resist is divided so that wirings on a circuit board are not short-circuited. The transmission cable connecting method according to claim 10,
As the circuit board, there is prepared a circuit board in which a heat transfer via for thermally connecting a connection surface between the signal transmission cable and the circuit board and a surface different from the connection surface is formed in the circuit board. ,
On the circuit board, a heating material having the self-propagating high temperature synthesis reaction is formed on a surface different from the connection surface between the signal transmission cable and the circuit board,
The heat of reaction when the exothermic material undergoes a self-propagating high-temperature synthesis reaction by external excitation is transferred to the connection surface via the heat transfer via, and the reaction heat is used to melt the solder paste, thereby forming the circuit. A transmission cable connecting method comprising connecting the wiring of a substrate and a conductor of the signal transmission cable.

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