JP4896840B2 - Manufacturing method of fine connector contact - Google Patents

Description

  The present invention relates to a method for manufacturing a fine connector contact that is necessary for contacts arranged at an extremely narrow pitch and requires precise dimensional accuracy, and more specifically, a conductor that constitutes a contact with functional ink ejected by an ink jet method. The present invention relates to a method for manufacturing a fine connector contact for forming a connector.

  Connector contacts that are placed on connecting parts such as plugs and sockets and make electrical contact with the contacts of the mating connecting parts are required to be elastic materials that maintain the pressing force required for the contact parts. The material was formed by stamping into a desired shape by pressing. On the other hand, with recent downsizing and higher functionality of electronic devices, it is desirable to reduce the size and pitch of connector contacts of connecting parts. However, due to problems such as dimensional accuracy and workability, machining Had its limitations.

  As a method of manufacturing a fine connector contact, a metal foil etching method, a photolitho etching method, and the like are known, but a sufficient thickness can be obtained for a connector contact that repeats contact with a mating contact. In addition, the wear resistance was poor and sufficient elasticity to stabilize the contact was not obtained.

  Further, as a method of manufacturing a finer connector contact, a functional ink in which conductive fine particles such as gold and silver are dispersed in a solvent is ejected from an ink jet head onto a substrate by using an ink jet method, and a solvent is obtained. There is known a manufacturing method for manufacturing a fine connector contact having a diameter of about 6 μm, which is used for connecting parts such as plugs and sockets (Non-Patent Document 1).

  Furthermore, since it is possible to form a fine conductive pattern with carbon nanotubes having excellent conductivity, a slurry containing carbon nanotubes and a solvent is applied on a substrate, dried, and then only in a region to be left as a conductive pattern. There is also known a method for forming a fine conductive pattern in which a binder is pattern-printed by an ink jet method, and a conductive pattern is formed with high definition by removing other portions (see Patent Document 1).

Prototype case of the National Institute of Advanced Industrial Science and Technology on the 15th page of the Nihon Keizai Shimbun published on November 17, 2006 Japanese Patent Laying-Open No. 2005-150107 (Summary, FIG. 1)

  However, the manufacturing method of forming the connector contact on the substrate by the ink jet method with the functional ink in which the conductive fine particles are dispersed in the solvent is formed only with the conductive fine particles in which the connector contacts are aggregated. There is a problem of lack of elasticity in the direction, a stable contact pressure due to elastic contact with the counterpart contact cannot be obtained, and long-term contact stability is lacking, and it has not been put into practical use at this time.

  In addition, the manufacturing method of forming a conductive pattern by applying a slurry containing carbon nanotubes only applies the slurry once on the substrate, so that a sufficient thickness cannot be obtained and a finely processed conductive pattern can be obtained. Even in this case, the conductive pattern formed by this method is formed with CNTs that do not have a sufficient thickness and agglomerate without gaps, so that it lacks elasticity, cannot obtain a stable contact pressure due to elastic contact, and wears. There is a problem that it is lacking in properties, and this method cannot be adopted for manufacturing a connector contact that repeats contact with a mating contact.

  The present invention has been made in consideration of such conventional problems, and is a fine connector contact for producing a connector contact having high dimensional accuracy, excellent elasticity, and detachable wear resistance. It aims at providing the manufacturing method of.

  In order to achieve the above-mentioned object, the manufacturing method of the fine connector contact according to claim 1 discharges the functional ink containing the conductive fine particles onto the conductor formed on the substrate by the ink jet method, and contacts the opposing contacts. A fine connector contact manufacturing method for forming on a conductor a fine connector contact that is electrically connected to each other by a butt contact with a CNT aggregate formed by tangling a large number of carbon nanotubes bent in the axial direction of the tube; A functional step in which conductive fine particles are dispersed in an organic solvent is discharged from an inkjet head onto a conductor formed on a substrate, and the functional ink on the conductor is baked or dried. The organic solvent is removed to form a film forming process in which the CNT aggregate and the conductive fine particles are aggregated, and the residual ink agent and the And forming a fine connector contact and a plurality of CNT aggregate and the conductive fine particles in contact coupling.

  Since the CNT aggregate and conductive fine particles dispersed in the organic solvent have an extremely small outer diameter, sedimentation is suppressed by the viscous resistance of the organic solvent and Brownian motion, and the CNT aggregate is dispersed uniformly in the organic solvent in a stable state. The

  The functional ink, which is a constituent material of the connector contact discharged from the inkjet head onto the conductor, can have a diameter of several μm or less developed on the conductor, so the connector can be used with high positional accuracy and pitch-to-pitch accuracy. A contact is formed.

  The CNT aggregate from which the organic solvent has been removed by baking or drying the functional ink and the conductive fine particles are contact-bonded to each other by removing the organic substances on the surface. Since the carbon nanotubes constituting the CNT aggregate are excellent in electrical conductivity, a low resistance connector contact is formed from the CNT aggregate and conductive fine particles that are in close contact with each other.

  In addition, since a large number of carbon nanotubes are bent in the axial direction of the tube, the carbon nanotubes are easily entangled with each other, and a CNT aggregate formed by entwining a large number of carbon nanotubes has voids between the carbon nanotubes. Each carbon nanotube has high tensile strength, is effective as an elastic material, and is excellent in repeated resilience that repeatedly deforms. Therefore, the entire CNT aggregate in a three-dimensional structure in which voids are generated between carbon nanotubes is elastic. Acts as a body, and the connector contact has elastic properties.

  The method of manufacturing a fine connector contact according to claim 2 is characterized in that the CNT aggregate is formed of a plurality of carbon nanotubes that are bent in an arbitrary direction in the axial direction of the tube and entangled with each other to form a spherical shape as a whole. .

  Since the carbon nanotubes bent in the axial direction of the tube are entangled to form a spherical CNT aggregate, a large number of gaps are formed between the carbon nanotubes, and the elastic body is not biased in a specific direction.

  According to a third aspect of the present invention, there is provided a method for producing a fine connector contact, wherein the protruding step and the film forming step are repeated to obtain a fine connector contact having a predetermined thickness.

  Since the functional ink ejected from the inkjet head is an ultrafine droplet, the drying property is very high, and the functional ink is immediately dried on the conductor. Therefore, the film formation process is extremely short, and by repeating the discharge process for discharging functional ink to the same location and the film formation process, a connector contact composed of the CNT aggregate and the conductive fine particles is formed in a desired film thickness. Can be stacked.

  The method for producing a fine connector contact according to claim 4 is characterized in that the functional ink contains nitrocellulose or hexamethylene diisocyanate as an auxiliary agent for the organic solvent.

  Nitrocellulose or hexamethylene diisocyanate decomposes and disappears together with the organic solvent in the film-forming step, but gives high elasticity to the structure by integrating the closely adhering CNT aggregate and conductive fine particles.

  After the film forming step, voids are formed between the CNT aggregates where nitrocellulose or hexamethylene diisocyanate has decomposed and disappeared, and voids where the CNT aggregates bend as elastic bodies are formed.

  According to the first aspect of the present invention, the fine connector contact can be manufactured with high accuracy by the inexpensive and excellent mass productivity method of the ink jet system.

  In addition, since the CNT aggregate formed by tangling a large number of carbon nanotubes is used as the nanomaterial constituting the connector contact, elastic characteristics can be obtained in the fine connector contact formed with high accuracy, and the contact with the mating contact can be achieved. Long-term contact stability is obtained.

  According to the second aspect of the present invention, since the CNT aggregate is spherical, the elastic characteristics of the connector contacts are not biased in a specific direction, and reliable elasticity is obtained in the film thickness direction.

  According to invention of Claim 3, the thickness of the connector contact to manufacture can be arbitrarily adjusted by repeating a discharge process and a film-forming process in a short time. Therefore, it is possible to manufacture a connector contact having a sufficient thickness and wear resistance capable of repeating contact with the mating contact.

  According to the invention of claim 4, it is possible to control the viscoelasticity at the time of manufacture, and it becomes possible to control the adjustment of the contact thickness and the like for increasing the dimensional accuracy and the elastic effect. The connector contact to be manufactured is given more elasticity, and the void disappears because the auxiliary agent disappears. Therefore, even if the thickness of the connector contact to be manufactured is made thinner, it is required for the connector contact. Elasticity is obtained.

  A method for manufacturing a fine connector contact according to an embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a perspective view of a connector connecting portion 10 composed of a fine connector contact 1, and FIG. 2 is a state including an ink 5 containing an organic solvent, conductive fine particles 6 and a CNT aggregate as a functional ink 2 in a discharge process. FIG. 3 is a schematic diagram of the fine connector contact 1 after the coating process.

  The fine connector contact 1 manufactured in the present embodiment is formed on each conductor end portion of the plurality of conductive patterns 4 wired on the insulating substrate 3 shown in FIG. A connector connection portion 10 is formed which makes contact with a contact of a mating connector (not shown) and is electrically connected to the contact of the mating connector.

  The pitch of the conductive pattern 4 is, for example, a 0.25 mm pitch that is difficult in machining. If the pitch accuracy between contacts is required to be 1/5, an error of 50 μm at maximum (100 μm on both sides) is required. Is required for forming the fine connector contact 1. Here, as a more strict requirement example, even when the pitch is 0.1 mm and the pitch accuracy is 1/10, an error forming position accuracy of a maximum of 10 μm (20 μm on both sides) is required for the fine connector contact. On the other hand, according to the ink jet system employed in the present embodiment, it is possible to make the droplet discharged from the ink jet head 1 fl (femtoliter) or less. In that case, the size of the droplet developed on the conductor 4 is small. The diameter can be reduced to 1 μm or less, the discharge position is controlled, and the functional ink 2 for forming the fine connector contact 1 is discharged from the inkjet head to produce the fine connector contact 1 that requires the above-mentioned accuracy. Is done.

  The conductive pattern 4 formed on the insulating substrate 3 with a pitch of 0.1 mm is also required to have the same level of accuracy. In addition to this ink jet method, any of metal foil etching methods, photolitho-etching methods, etc. It can also be formed by a method.

  In general, the ink jet method is a method of performing recording by supplying ink to fine discharge nozzles of an ink jet printer, pressurizing the ink held in the discharge nozzles, and discharging ink droplets onto a recording sheet. As described above, in the present invention, the functional ink 2 containing the material for forming the fine connector contact 1 is ejected from the ink jet head onto the conductor and the pattern of the functional ink 2 is formed on the conductor in a non-contact manner. This is the ning method. The inkjet head that ejects the functional ink 2 uses a thermal jet method in which ink is heated to generate bubbles and the ink is ejected from the inkjet head with the pressure, and a piezoelectric element is used as a pressure generation source. There is a piezo type in which the wall is deformed by a piezoelectric element and ink filling the pressure chamber is pressurized and ejected. Here, it is preferable to use a piezo type inkjet head.

  The functional ink 2 ejected from the ink jet head contains a forming material for forming the fine connector contact 1 and, as schematically shown in FIG. CNT aggregates 7, which are entangled with each other in a spherical shape, are dispersed in an ink 5 containing an organic solvent.

  CNTs are produced by various methods such as arc discharge, laser evaporation, chemical vapor deposition, etc., but high purity single phase CNTs are obtained, and are produced by the super-growth CVD method excellent in mass productivity. The manufactured CNT is a cylindrical body with a nano-micron diameter mainly composed of carbon. It has excellent electrical conductivity and at the same time has a very high tensile strength and is effective as an elastic material. Is excellent.

  In the present invention, for example, in the growth process of CNTs by the above manufacturing method, an object extending to a position higher than the catalyst layer is formed around the catalyst layer and the catalyst layer, and the CNT is separated from the object along the object from the catalyst layer. CNTs are used which are grown while being bent by the action of van der Waals force and bent in the axial direction of the tube. The cylindrical surface forming the tube of CNT is formed of a carbon network structure of a honeycomb-like 6-membered ring structure, but the bent portion curved in the axial direction of the tube is a carbon of a 5-membered ring structure or a 7-membered ring structure. It has a mesh structure.

  Thus, when the CNTs bent in the axial direction are collected in an amount such that, for example, the overall size is about several tens of nanometers, the bent CNTs are entangled and a large number of CNTs in an intertwined state are graphite. Since a strong van der Waals force works between the layers, the CNT aggregate 7 that is firmly bonded is formed.

  The conductive fine particles 6 are blended for the purpose of reducing the conductor resistance of the fine connector contact 1 formed through the film-forming process, and a metal material such as Au, Ag, Ni, or Mn has an outer diameter of several nm. However, it is not necessarily limited to this size within the scope of the object of the present invention. Further, depending on the size, a nickel layer may be applied around a spherical core formed from a resin, and gold plating may be applied to the outer periphery thereof.

  For example, ether, benzene, ethyl acetate, isopropyl alcohol, ethanol, diethyl ether, etc. can be used as long as the ink 5 containing an organic solvent is discharged onto the conductor 4 and then burned away by volatilization or combustion decomposition by heating and baking. The ink viscosity of the functional ink 2 can be adjusted by using an appropriate amount of butyl carbitol, isobutyl carbitol, or the like.

  Since the outer diameter of the CNT aggregate 7 and the conductive fine particles 6 blended in the organic solvent 5 is as small as several nanometers to several tens of micrometers, sedimentation is suppressed by the viscous resistance of the organic solvent 5 and Brownian motion, and evenly. And dispersed in the organic solvent 5 in a stable state.

  The viscosity of the functional ink 2, that is, the viscosity that can be normally ejected from the inkjet head at room temperature is preferably, for example, 40 mPa · s or less, and a predetermined viscosity modifier is blended in the organic solvent 5 for viscosity adjustment. You may let them.

  The functional ink 2 may be added with an auxiliary agent having an excellent elastic modulus such as nitrocellulose and hexamethylene diisocyanate. In particular, nitrocellulose imparts high elasticity to the fine connector contact 2 formed by baking or drying the functional ink 2 and is excellent in drying property when formed into a coating film. Also, if a self-combustible material such as nitrocellulose is pulverized to a particle size of μm and dispersed in the organic solvent 5, the auxiliary agent burns and burns out after being discharged onto the conductor 4. Thus, the CNT aggregate 7 acting as an elastic body becomes a space to be bent, and the elastic coefficient of the fine connector contact 2 can be further reduced to obtain flexibility.

  In manufacturing the fine connector contact 1, the functional ink 2 having the above-described configuration is ejected as an ink droplet from an ink jet head onto each conductor end portion of the conductive pattern 4 on the insulating substrate 3 and attached. The size (amount) of the ink droplet of the functional ink 2 is adjusted by the width of the conductive pattern 4 to be attached, and developed on the conductive pattern 4 with an error of 20 μm or less with respect to the width of the conductive pattern 4. In this discharging process, a large number of CNT aggregates 7 and conductive fine particles 6 are sterically dispersed on the conductive pattern 4 with an intermediary between the organic solvent 5 and the auxiliary agent interposed therebetween.

  Thereafter, when the functional ink 2 adhering to the conductive pattern 4 is dried or baked, the auxiliary agent in the case of being added with the organic solvent 5 is CNT that has been dispersed due to volatilization or combustion decomposition of the liquid component. The aggregate 7 and the conductive fine particles 6 aggregate and contact with each other as shown in FIG.

  The fine connector contact 1 is formed by contact bonding of CNT aggregates 7 made of a large number of CNTs excellent in electrical conductivity and conductive fine particles 6, so that it has excellent electrical conductivity and is electrically connected to the contact of the mating connector. It acts as a low resistance contact.

  Further, since the CNT aggregate 7 is formed by entwining a large number of CNTs, a space in which the CNT is bent is formed in the CNT aggregate 7, and each CNT aggregate 7 itself acts as a high elastic body. . As a result, the fine connector contact 1 also has elasticity in the film thickness direction (vertical direction in FIG. 3), and a predetermined contact pressure is obtained with the contact of the mating connector that contacts in the film thickness direction. Stable electrical connection is possible.

  When an auxiliary agent excellent in elastic modulus is added to the functional ink 2, the fine connector contact 1 has higher elasticity. In particular, when an auxiliary agent that burns and burns out is added, the auxiliary agent that has secured the three-dimensional structure of the CNT aggregate 7 and the conductive fine particles 6 is burned down by combustion and voids are formed. As a result, a sufficient film thickness can be obtained for the fine connector contact 1 and a space in which the CNT aggregate 7 acting as an elastic body bends can be provided, so that the fine connector contact 2 can be more elastic.

  When the predetermined thickness cannot be obtained in the fine connector contact 1, the discharge process and the film forming process are further repeated on the CNT aggregate 7 and the conductive fine particles 6 that are contact-bonded after the film forming process is completed. The body 7 and the layer composed of the conductive fine particles 6 are stacked to form the fine connector contact 1 having a desired thickness.

  The fine connector contact manufactured in this manner can be formed at one end of the conductive pattern 4 shown in FIG. 1 and can be formed in other applications where it is necessary to form a fine conductor connection portion. 4 and 5 show a connection plate 21 used for a semiconductor socket that is electrically connected to a circuit board by a mounting method similar to that of a surface-mount type semiconductor package such as LGA or BGA, or a connector contact that makes a pressing contact in the vertical direction. Another embodiment of the present invention in which a fine connector contact 20 is formed is illustrated. In the second embodiment, the manufacturing method for manufacturing the fine connector contact 20 is the same as that of the first embodiment, and therefore, the common components will be described using the same numbers.

  The connection plate 21 such as a semiconductor socket has through holes penetrating the front and back at a plurality of positions on the insulating substrate 22, and a metal conductor portion 23 such as silver is embedded in each through hole. Each through-hole is formed, for example, corresponding to a portion where the electrode on the bottom surface side of the semiconductor package and the land on the surface side of the circuit board are exposed, whereby the surface side of the metal conductor portion 23 is used as an electrode. The back side faces the land.

  As shown in FIG. 5, the fine connector contact 20 discharges the functional ink 2 to the front surface side and the back surface side of the metal conductor portion 23 by the ink jet method with respect to the connection plate 21 on which the metal conductor portion 23 is formed. Through a discharge process and a film forming process, the metal conductor portion 23 is formed in a substantially hemispherical shape covering the front side and the back side.

  For example, the semiconductor package and the circuit board and the connection plate 21 are positioned relative to each other by positioning means (not shown). Even if the distance between the electrodes of adjacent semiconductor packages or the lands of the circuit board is very small, Since the fine connector contact 20 can be formed with high accuracy in the facing portion, there is no short circuit between the electrodes and between the lands via the fine connector contact 20.

  The semiconductor socket sandwiches the connection plate 21 between the bottom surface of the semiconductor package and the surface of the circuit board, and electrically connects the corresponding electrode of the semiconductor package and the land of the circuit board via the metal conductor portion 23. Even if the exposed surface of the metal conductor portion 23 is minute and cannot obtain a predetermined elasticity, the fine connector contact 20 has elasticity, so that both can be stably electrically connected.

  In each of the embodiments described above, the fine connector contacts 1 and 20 are brought into direct contact with the mating contact or electrode. However, when there is a possibility of repeated wear, the conductive fine particles 6 to be fused or the CNT aggregate When the body 7 may be vaporized, a conductive protective film may be attached to the surface of the formed fine connector contacts 1 and 20 to prevent the loss due to wear or vaporization.

  In addition, the CNT may be either a single-walled carbon nanotube (SWCNT) formed by rolling a graphite hexagonal mesh plane into a cylindrical shape, or a multi-walled carbon nanotube (MWCNT) in which they are nested.

  In addition, the CNT aggregate has been described with an example in which a large number of CNTs are entangled in a spherical shape. You may form with a carbon nanotube.

  The present invention is suitable for manufacturing fine connector contacts formed on a conductor at a narrow pitch.

1 is a perspective view of a connector connecting portion 10 made of a fine connector contact 1. FIG. It is a schematic diagram of the functional ink 2 in the ejection process. It is a schematic diagram of the fine connector contact 1 after a membrane | film | coat process. It is a perspective view of the connection plate 21 of a semiconductor socket. FIG. 4 is a longitudinal sectional view of the connection plate 21 showing a state in which fine connector contacts 20 are formed on the connection plate 21.

Explanation of symbols

1, 20 Fine connector contact 2 Functional ink 4 Conductor (conductive pattern)
5 Ink Containing Organic Solvent (Organic Solvent) 6 Conductive Fine Particles 7 CNT Aggregate 23 Conductor (Metal Conductor Part)

Claims (4)

A fine connector contact that discharges functional ink containing conductive fine particles onto a conductor formed on a substrate by an inkjet method, and forms a fine connector contact on the conductor that is electrically connected to the opposing contact by butt contact. A manufacturing method of
A functional ink in which a large number of carbon nanotubes bent in the axial direction of the tube are entangled with each other and a large number of conductive fine particles dispersed in an organic solvent is formed on the substrate from the inkjet head. A discharge step of discharging onto the conductive material;
It consists of a film forming process in which the functional ink on the conductor is baked or dried to remove the organic solvent, and the CNT aggregate and the conductive fine particles are aggregated.
A method of manufacturing a fine connector contact, comprising forming a fine connector contact having elastic properties from a large number of CNT aggregates and conductive fine particles that are contact-bonded to each other. 2. The method of manufacturing a fine connector contact according to claim 1, wherein the CNT aggregate is formed of a plurality of carbon nanotubes which are bent in an arbitrary direction in the axial direction of the tube and are entangled with each other to form a spherical shape as a whole. . The method of manufacturing a fine connector contact according to claim 1 or 2, wherein the protruding step and the film forming step are repeated to form a fine connector contact having a predetermined thickness. The method for producing a fine connector contact according to any one of claims 1 to 3, wherein the functional ink contains nitrocellulose or hexamethylene diisocyanate as an auxiliary agent for the organic solvent.

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