JP2009239266A - Both-sides conduction method for wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a both-sides conduction method for a wiring board, by which wiring patterns on both-sides of the wiring board having conductor layers constituting the wiring patterns and formed on the both-sides surfaces of a synthetic resin film base material are electrically conducted to each other with good efficiency, and the conduction portion is stabilized with low resistance. <P>SOLUTION: The wiring board 1A, which has the conductor layers 3 and 4 constituting the wiring patterns and formed on the both-sides surfaces of the synthetic resin film base material 2, is compressed at conduction planned positions P of the both-sides wiring patterns from both sides of the wiring board 1A with a pair of ultrasonic bonding tools 5 and 6 to bring the both-sides conductors 3 and 4 into contact with each other by forcing a synthetic resin present between the conductor layers 3 and 4 at the conduction planned positions P toward a peripheral side, and the both-sides conductors contacted with each other are bonded together by ultrasonic vibrations from the ultrasonic bonding tools 5 and 6. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  This invention is an electromagnetic tag readable IC tag used as an air tag, a logistics management label, an unmanned ticket gate, a financial card, a flexible printed wiring board used in various electrical products, The present invention relates to a method for electrically connecting a part of the front and back wiring patterns between the front and back surfaces in a wiring board in which a conductor layer constituting a wiring pattern is formed on the front and back surfaces of a synthetic resin film substrate.

  In this specification and claims, the term “aluminum” is used to include aluminum and its alloys, and the term “copper” is used to include copper and its alloys.

  In general, this type of IC tag has a metal foil made of polyethylene or terephthalate or polyethylene naphthalate attached to the front and back surfaces of aluminum or copper, and a wiring pattern is printed on the metal foil with resist ink. After the wiring circuit is formed by etching, electrical connection is made between the front and back wiring patterns at a required position, and an IC chip is mounted to form a card.

  As a conduction means between the front and back wiring patterns, a through-hole method is often used in which a hole is formed at a conduction position and a plating layer or a conductive paste coating layer is formed continuously on the front and back through the hole. However, such a through-hole method has a problem that it takes time and effort to process, is inferior in production efficiency, has a high processing cost, and is liable to cause peeling or cracking in the conductive portion due to bending of the film substrate.

  Therefore, as a conduction means instead of the through-hole method, crimping is performed between the metal plate with unevenness and the metal protrusion, and the resin film and the adhesive layer of the base material are partially broken, thereby A crimping method that physically contacts metal foils has been proposed (Patent Document 1).

JP 2002-7990 A

  However, in the above-described crimping method, the conduction resistance of the crimping portion is as high as 0.04Ω (see paragraph 0052 of Cited Document 1), so that the electromagnetic wave energy is changed to heat with high resistance when reading the electromagnetic wave of the IC tag. There was an inconvenience that it would end up. In addition, the crimping process has low equipment costs and good productivity.However, since the conductor layers on the front and back surfaces are in contact with each other in the crimping part, the contact part is likely to loosen due to thermal shock or bending. There was a problem that there was a concern about poor continuity.

  The present invention has been made in view of such a technical background, and in a wiring board in which a conductor layer constituting a wiring pattern is formed on the front and back surfaces of a synthetic resin film substrate, between the wiring patterns on the front and back sides. An object of the present invention is to provide means capable of efficiently and reliably conducting electricity and stabilizing a conduction part with low resistance, and thereby contributing to improvement in reliability of an IC tag and reduction in manufacturing cost.

  As a result of intensive studies in order to achieve the above object, the present inventor combines parts of the conductor layers on the front and back sides of the wiring board by combining clamping pressure using ultrasonic bonding and ultrasonic bonding. The present invention has been completed by finding that the electrical conduction can be performed extremely efficiently and reliably, and that the formed conduction part is stably maintained at a very low resistance over a long period of time. That is, in order to achieve the above object, the present invention provides the following means.

  [1] In a wiring board in which a conductor layer constituting a wiring pattern is formed on the front and back surfaces of a synthetic resin film base material, when electrically connecting a part of the wiring pattern between the front and back, By sandwiching from both sides of the wiring board with the ultrasonic bonding tool, the synthetic resin present between the conductor layers of the planned conduction part is pushed away to the peripheral side to bring the front and back conductors into contact with each other. A method for conducting the front and back of a wiring board, wherein the bodies are bonded together by ultrasonic vibration from an ultrasonic bonding tool.

  [2] The wiring board according to item 1 above, wherein when the planned conduction part is clamped, the conductive planning part is clamped from both sides of the wiring board while performing ultrasonic vibration with a pair of ultrasonic bonding tools. Front and back conduction method.

  [3] The circuit board front-back conduction method according to item 1 or 2, wherein a protrusion is provided on at least one of the opposing surfaces of the pair of ultrasonic connectors.

  [4] A protrusion is provided only on one of the opposing surfaces of the pair of ultrasonic couplers, and the thickness of the conductor layer on the side in contact with the ultrasonic coupler having the protrusions is 3. The front and back conduction method for a wiring board according to item 1 or 2, wherein the thickness is set to be larger than the thickness of the conductor layer on the other side.

  [5] A protrusion is provided only on one of the opposing surfaces of the pair of ultrasonic couplers, and the thickness of the conductor layer on the side that contacts the ultrasonic coupler having the protrusions is 3. The front-and-back conduction method for a wiring board according to item 1 or 2, which is set smaller than the thickness of the conductor layer on the other side.

  [6] The conductor layer is made of an aluminum foil having a thickness of 7 to 50 μm, the clamping pressure is 0.01 to 1 MPa, and the ultrasonic energy per protrusion of the ultrasonic connector is 0.01 to 100 J. 6. The front-and-back conduction method for a wiring board according to any one of items 1 to 5, which is set to 1 above.

  [7] The conductor layer is made of a copper foil having a thickness of 7 to 50 μm, the clamping pressure is 0.01 to 1 MPa, and the ultrasonic energy per protrusion of the ultrasonic connector is 0.01 to 100 J. 6. The front-and-back conduction method for a wiring board according to any one of items 1 to 5, which is set to 1 above.

  [8] The front and back conduction method for a wiring board according to any one of items 1 to 7, wherein the synthetic resin film base material is made of polyethylene terephthalate or polyethylene naphthalate having a thickness of 20 to 50 μm.

  According to the front and back conduction method of the wiring board according to the invention of [1], the conductive resin between the front and back conductor layers is pushed to the peripheral side by pressing the conductive part of the wiring board from both sides to contact the conductive metals on the front and back sides. Then, the conductors on the front and back sides are sufficiently integrated at the conduction part, so that the conduction resistance becomes extremely low, and conduction failure occurs even if thermal shock or bending is applied to this part. There is no fear and a good conduction state is maintained for a long time. In addition, since the above-described clamping pressure is performed using an ultrasonic bonding tool, a series of operations from the clamping pressure to the ultrasonic bonding can be performed continuously and efficiently in a short time, and a separate additional process can be performed. It is not necessary and productivity can be improved, and the equipment cost and processing cost can be reduced. Therefore, an IC tag configured using a wiring board that is conductive on the front and back sides by this front-and-back conduction method can obtain high reliability and durability of electromagnetic wave reading and can be manufactured at low cost.

  According to the invention of [2], since the ultrasonic vibration from the ultrasonic bonding tool is applied to the planned conduction part from the stage of clamping the planned conduction part between the pair of ultrasonic bonding tools, the conduction on the front and back sides in the planned conduction part is performed. The body can be more fully integrated, which can further reduce the conduction resistance and maintain a good conduction state for a longer period of time.

  According to the invention of [3], since the projection is provided on at least one of the opposing surfaces of the pair of ultrasonic couplers, the synthetic resin between the conductor layers can be easily pushed to the peripheral side by the projection during clamping. There is an advantage that the conductive layers on the front and back sides can be contacted more reliably and the conduction resistance can be further reduced.

  According to the invention of [4], when the wiring board is clamped by using a pair of ultrasonic bonding tools, the conductor layer of the wiring board on the side to be brought into contact with the ultrasonic bonding tool having the protruding portions extends along the protruding portions. However, since the conductor layer is designed to be thicker than the other conductor layer, breakage due to stretching is less likely to occur.

  According to the invention of [5], the conductor layer on the side to be brought into contact with the ultrasonic bonding tool having a flat opposing surface is thicker than the conductor layer on the side to be brought into contact with the ultrasonic bonding tool having the protrusions. Therefore, when a wiring board is clamped using a pair of ultrasonic bonding tools, continuous cracks (cracks that inhibit conduction) are generated in the conductor layer on the side where the opposing surface is brought into contact with the flat ultrasonic bonding tool. Can be sufficiently prevented.

  According to the invention of [6], the conductor layer is made of an aluminum foil having a thickness of 7 to 50 μm, the sandwiching pressure is 0.01 to 1 MPa, and the ultrasonic energy per one protrusion of the ultrasonic bonding tool is 0. Since it sets to 01-100J, favorable conduction | electrical_connection between the aluminum layers of front and back can be taken reliably.

  According to the invention of [7], the conductor layer is made of a copper foil having a thickness of 7 to 50 μm, the sandwiching pressure is 0.01 to 1 MPa, and the ultrasonic energy per protrusion of the ultrasonic bonding device is 0. Since it sets to 01-100J, favorable conduction | electrical_connection between the copper layers of front and back can be taken reliably.

  According to the invention of [8], since polyethylene terephthalate or polyethylene naphthalate having a thickness of 20 to 50 μm is used as the synthetic resin film substrate, the resin of the film substrate is used during clamping between a pair of ultrasonic connectors. Is surely pushed away to the peripheral side, and the conductive layers on the front and back sides are in a better contact state, and there is an advantage that the conduction resistance can be further reduced.

It is a longitudinal cross-sectional view which shows an example of the wiring board to which this invention is applied. FIG. 5A shows a pinching process for the wiring board, in which FIG. 9A is a longitudinal cross-sectional view before the start, and FIG. 5B is a vertical cross-sectional view during the pinching process. It is a longitudinal cross-sectional view of the wiring board after the front-back conduction obtained through the process of FIG. The clamping process with respect to the wiring board of another form is shown, (A) A figure is a longitudinal cross-sectional view before a start, (B) figure is a longitudinal cross-sectional view in the same clamping process. It is a longitudinal cross-sectional view of the wiring board after the front-back conduction obtained through the process of FIG. It is an enlarged plan view of the opposing surface (contact surface with a wiring board) of the ultrasonic bonding tool having a protrusion.

  Hereinafter, a front and back conduction method of a wiring board according to the present invention will be specifically described with reference to the drawings. FIG. 1 is a longitudinal sectional view showing an example of a wiring board to which the present invention is applied, FIG. 2 (A) is a longitudinal sectional view before the start of the pressing process on the wiring board, and FIG. 2 (B) is during the pressing process. FIG. 3 is a longitudinal sectional view of the wiring board after the front and back conduction.

  As shown in FIG. 1, the wiring board 1 </ b> A is obtained by forming conductor layers 3 and 4 constituting a wiring pattern on the front and back surfaces of the synthetic resin film base 2. The conductor layers 3 and 4 are formed of a metal foil bonded to the surface of the synthetic resin film substrate 2 via an adhesive (not shown), and after the bonding, a wiring pattern is formed with a resist ink. Is printed and etched to form a required wiring pattern. Further, by using the metal foils having different thicknesses, one conductor layer 3 is set thicker than the other conductor layer 4.

  In the front and back conduction method of the present invention, in order to electrically connect a part of the wiring pattern in the wiring board 1A between the front and back, as shown in FIGS. 2A and 2B, the wiring board 1A is scheduled to be conducted. The part P is clamped from both sides with a pair of opposing ultrasonic connectors 5 and 6. Here, as shown in FIG. 2A, the opposing surface (end surface) of one ultrasonic bonding tool 5 has a truncated cone-shaped protrusion 5a, but the other ultrasonic bonding tool 6 has an opposing surface. As shown in FIG. 2B, the ultrasonic bonding tool 5 having the protrusions 5a is brought into contact with the conductor layer 3 on the thick side of the wiring board 1A and the wiring board 1A is thin. The ultrasonic bonding tool 6 having a flat opposing surface is brought into contact with the conductor layer 4 on the side and is pressed.

  By this clamping process, as shown in FIG. 2 (B), the protruding portion 5a of one ultrasonic bonding tool 5 compresses the wiring board 1A in the thickness direction and dents it into the other ultrasonic bonding tool 6. In this approaching process, the resin of the film base 2 existing between the two conductive layers 3 and 4 is pushed away to the peripheral side, and the thick conductive layer 3 is stretched along the protruding portion 5a. The conductor layers 3 and 4 on the front and back sides are in contact with each other at the tip end of the protrusion 5a. At this time, the conductor layer 4 on the thin side of the wiring board 1A is hardly deformed (see FIG. 2B).

  Thus, after the wiring board is clamped between the ultrasonic bonding tools 5 and 6, the ultrasonic bonding by the ultrasonic bonding tools 5 and 6 is performed in the pinched state, so that the conductive layers on the front and back surfaces in contact with each other 3 and 4 are joined and integrated. As a result, as shown in FIG. 3, a wiring substrate 1 </ b> B in which the conductive layers 3 and 4 on the front and back sides are partly electrically connected to C is obtained.

  In this wiring board 1B, since the conductive layers 3 and 4 on the front and back sides are completely integrated at the conductive portion C, the conductive resistance becomes extremely small, and the conductive portion C is conductive even if a thermal shock or bending is applied. A good conduction state is maintained over a long period without causing a defect. Therefore, the IC tag manufactured using this wiring board 1B can obtain high reliability and durability in electromagnetic wave reading.

  Further, in the front and back conduction method of the present invention, the pinching of the wiring board 1A is performed using the ultrasonic bonding tools 5 and 6 for bonding the conductor layers of the front and back wiring patterns. Can be performed efficiently and continuously in a short time, the productivity is increased, and no additional process is required, and the equipment and processing costs can be reduced. The manufacturing cost of an IC tag configured using the wiring board 1B that is electrically connected to the front and back surfaces can be greatly reduced.

  Next, FIGS. 4A and 4B show an example in which the front / back conduction method of the present invention is applied to a wiring board of another form. This wiring board 1C is formed by forming conductor layers 3 and 4 constituting a wiring pattern on the front and back surfaces of the synthetic resin film substrate 2, and these conductor layers 3 and 4 are formed of the synthetic resin film substrate 2 It is formed with a metal foil that is bonded to the surface of the substrate via an adhesive (not shown). After the bonding, the wiring pattern is printed with resist ink and etched to form the required wiring pattern. Yes. Thus, the embodiment is such that the thickness of the conductor layer 3 on the side where the ultrasonic bonding tool 5 having the protrusions 5a contacts is set smaller than the thickness of the conductor layer 4 on the other side. Is different. By performing the same clamping process as in the above embodiment on the wiring board 1C, as shown in FIG. 5, the wiring board 1D in which the conductor layers 3 and 4 on the front and back sides are electrically connected at a part C is obtained. can get. In this embodiment, the conductor layer 4 on the side opposite to the side in contact with the ultrasonic bonding tool 5 having the projection 5a (on the side in contact with the ultrasonic bonding tool 6 having a flat opposing surface) Since it is thicker than the conductor layer 3 on the side to be brought into contact with the ultrasonic bonding tool 5 having 5a, when the wiring substrate 1C is clamped using the pair of ultrasonic bonding tools 5 and 6, the opposing surface is flat. There exists an advantage which can fully prevent that the continuous crack (crack which inhibits conduction | electrical_connection) arises in the conductor layer 4 of the side contacted with the sonic connector 6. FIG.

  The synthetic resin film substrate 2 may be any resin material having plastic deformability that allows the resin component to plastically flow and move to the peripheral side due to the clamping pressure between the ultrasonic connectors 5 and 6. A film made of a thermoplastic resin can be used, and a film made of polyethylene terephthalate (hereinafter abbreviated as PET) or polyethylene naphthalate (hereinafter abbreviated as PEN) is particularly preferable. Further, the thickness of the synthetic resin film base 2 is in the range of 20 to 50 μm in order to ensure the strength as a wiring board and to avoid the breakage of the conductor layers 3 and 4 during the clamping process. Is preferred.

  The conductor layers 3 and 4 constituting the front and back wiring patterns are not particularly limited, and examples thereof include a metal foil and a conductive ink layer. The metal foil is not particularly limited, but an aluminum foil and a copper foil are recommended because it is desirable to have good electrical conductivity and excellent spreadability during pressing. Moreover, as thickness of these aluminum foil and copper foil, the range of 7-50 micrometers is preferable. The adhesive used for bonding the metal foils 3 and 4 to the synthetic resin film substrate 2 is not particularly limited, and examples thereof include polyester adhesives and polyisocyanate adhesives. .

  Although it does not specifically limit as said conductive ink, For example, the conductive ink etc. which contain a conductive substance and a binder component are mentioned. The conductive material is not particularly limited, and examples thereof include metals (silver, copper, etc.), metal oxides (tin oxide, zinc oxide, antimony oxide, silver oxide, indium oxide, etc.), graphite, carbon Examples thereof include inorganic materials coated with black and metal.

  The binder component is not particularly limited. For example, polyester resin, polyolefin resin, chlorinated polyolefin, epoxy resin, brominated epoxy resin, phenol resin, acrylic resin, polyamideimide, vinyl chloride-vinyl acetate Examples thereof include polymers and modified polyvinylidene fluoride.

  Although it does not specifically limit as a solvent added to the said conductive ink, For example, an aliphatic hydrocarbon solvent (n-heptane, n-hexane, cyclohexane, etc.), an aromatic hydrocarbon solvent (toluene, xylene, etc.), petroleum System solvents and the like.

  By using the conductive ink and printing by a printing method such as screen printing, flexographic printing, and gravure printing, the conductor layers 3 and 4 that become the front and back wiring patterns can be formed.

  The preferred range of the clamping pressure applied between the ultrasonic bonding tools 5 and 6 during the clamping process varies depending on the type and thickness of the conductor layers 3 and 4, but the conductor layer has a thickness of 7 In the case of an aluminum foil having a thickness of ˜50 μm, the range of 0.01 to 1 MPa is recommended, more preferably 0.1 to 0.3 MPa, and the conductor layer is made of a copper foil having a thickness of 7 to 50 μm. In some cases, the range of 0.01 to 1 MPa is recommended, and more preferably 0.05 to 0.5 MPa.

  The ultrasonic energy applied per one protrusion of the ultrasonic bonding device has a suitable range depending on the material type and thickness of the conductor layers 3 and 4, but the conductor layer has a thickness of 7 to 50 μm. When the aluminum foil is made of aluminum foil, the range of 0.01 to 100 J is preferred, with 0.1 to 25 J being particularly preferred. When the conductor layer is made of copper foil with a thickness of 7 to 50 μm, 0.01 to 100 J is preferred. The range is preferably 0.5 to 80 J.

  Thus, in the production line, a conduction check process is arranged next to the ultrasonic bonding process, and the resistance value of the front and back conduction parts of the wiring board is measured in this conduction check process, thereby confirming the front and back conduction state. .

  In the pinching process according to the present invention, as shown in FIGS. 2 and 4, for example, one ultrasonic bonding tool 5 is opposed to each other as a pair of ultrasonic bonding tools in addition to using one having a protruding portion 5 a on the opposite surface. You may use what has a projection part in a surface. In the latter case, the protrusions of the pair of ultrasonic couplers may be arranged to face each other or to mesh with each other. Further, the protruding portion on the opposite surface of the ultrasonic bonding tool may have a configuration in which a plurality of the protruding portions 5a as illustrated are provided apart from each other, or a configuration in which one protruding portion is provided. May be. Further, the shape of the protrusion is not particularly limited, and various shapes such as a truncated cone shape as well as a truncated cone shape as in the above embodiment can be adopted. Further, for example, when the application is an IC tag or the like, two ultrasonic bonding tools 5 having a plurality of protrusions 5a as shown in FIGS. The front and back continuity may be formed by performing the clamping process at each position, but one ultrasonic jig is provided with an ultrasonic bonding portion 5 as shown in FIGS. It is preferable to simultaneously form the front and back conduction at the two positions separated by the clamping pressure due to the above. In the latter case, there is an advantage that the productivity can be improved about twice.

  In addition, when the opposing surfaces of the pair of ultrasonic connectors are both flat surfaces of a certain extent, the resin of the film base is sufficiently removed to the peripheral side even if the above-described clamping process is performed. It becomes difficult to make the front and back conductor layers sufficiently contact each other. Accordingly, the pair of ultrasonic bonding tools used in the present invention has a configuration having a protrusion on at least one of the opposing surfaces, or a configuration in which the ultrasonic bonding device itself has a protruding end shape like a rod. Is preferred.

FIG. 6 shows an example of an enlarged plan view of the facing surface (contact surface with the wiring board) of the ultrasonic bonding tool 5 having the protrusion 5a. For example, a configuration in which 30 to 200 protrusions 5a are provided apart from each other in a 4 mm ² region on the facing surface is employed, but the arrangement density is not particularly limited.

  Further, in the clamping process, the planned conduction position of the wiring board is heated (for example, when the clamping is performed by a pair of ultrasonic bonding tools, the ultrasonic conduction is performed by the ultrasonic bonding tool to heat the planned conduction position). In this case, the resin of the film base material can be easily softened or deformed to some extent, so that the movement of the resin to the peripheral side (plastic flow) at the clamping portion can be further facilitated. There is.

  Next, specific examples of the present invention will be described, but the present invention is not particularly limited to these examples.

<Example 1>
After attaching a 10 μm thick aluminum foil and a 30 μm thick aluminum foil to each of the front and back surfaces of a film substrate made of PET having a thickness of 38 μm via a polyester-based adhesive, By printing and etching resist ink in a predetermined pattern, a wiring board having aluminum layers constituting a predetermined wiring pattern on the front and back surfaces was produced. Next, as shown in FIGS. 2 (A) and 2 (B), using a pair of ultrasonic couplers having a plurality of protrusions on one opposing surface, the ultrasonic coupler having the protrusions is thick. The wiring board was sandwiched between the two aluminum layers of the clamping part by clamping the wiring board with a clamping pressure of 0.15 MPa and a displacement of 0.05 mm between these ultrasonic bonding tools in an arrangement in contact with the 30 μm aluminum foil side. The PET resin (film base material) is pushed away to the peripheral side, the front and back aluminum layers are brought into contact with each other, and ultrasonic vibrations are applied to both ultrasonic bonding devices in this state, and the ultrasonic energy per protrusion is 25 J. 0.09 second ultrasonic bonding was performed to join and integrate the front and back aluminum layers to obtain a wiring board in which the front and back wiring patterns were electrically connected.

<Example 2>
A wiring board in which the wiring patterns on the front and back sides were electrically conducted was obtained in the same manner as in Example 1 except that the clamping pressure in the clamping process was changed to 0.12 MPa.

<Example 3>
A wiring board in which the wiring patterns on the front and back sides were electrically conducted was obtained in the same manner as in Example 1 except that a film base made of PEN having a thickness of 38 μm was used as the film base.

<Example 4>
A wiring board in which the wiring patterns on the front and back sides were electrically conducted was obtained in the same manner as in Example 1 except that the ultrasonic energy per protrusion was set to 2J.

<Example 5>
The wiring patterns on the front and back sides were electrically conducted in the same manner as in Example 1 except that the clamping pressure in the clamping process was set to 0.25 MPa and the ultrasonic energy per protrusion was set to 0.4 J. A wiring board was obtained.

<Example 6>
A wiring board having a copper layer constituting a predetermined wiring pattern on the front and back in the same manner as in Example 1 except that a 10 μm thick copper foil and a 30 μm thick copper foil were used instead of the front and back aluminum foils. The wiring board is produced and clamped between a pair of ultrasonic joints in the same manner as in Example 1, and then ultrasonic vibration is applied to both ultrasonic joints to obtain an ultrasonic energy of 80 J per protrusion. Then, ultrasonic bonding was performed for 0.13 seconds, and the copper layers on the front and back sides were joined and integrated to obtain a wiring board in which the wiring patterns on the front and back sides were electrically conducted.

<Example 7>
A wiring board in which the wiring patterns on the front and back sides were electrically conducted was obtained in the same manner as in Example 6 except that the ultrasonic energy per protrusion was set to 10 J.

<Example 8>
The wiring patterns on the front and back sides were electrically conducted in the same manner as in Example 6 except that the clamping pressure in the clamping process was set to 0.25 MPa and the ultrasonic energy per protrusion was set to 0.5 J. A wiring board was obtained.

<Comparative Example 1>
A wiring board in which the front and back wiring patterns are electrically conductive was obtained by performing crimping bonding by a crimping method on the wiring board that was not conducted on the front and back sides in the same manner as in Example 1.

  About the wiring board which carried out the front and back conduction obtained in the said Examples 1-8 and the comparative example 1, the resistance value of the front and back conduction | electrical_connection part was measured with the milliohm meter at room temperature. Moreover, about the wiring board obtained in the Example, the resistance value of the front and back conductive parts was measured after a cycle of 100 hours at −40 ° C. for 1 hour at room temperature, 10 minutes at 120 ° C. and 1 hour at 120 ° C. . These results are shown in Table 1. The resistance values in Table 1 are average values of 10 samples each.

  As is apparent from Table 1, according to the front / back conduction method of the present invention, the conduction resistance of the front / back conduction part is much smaller than that of the front / back conduction part according to the conventional crimping method, and very excellent conductivity is obtained. Furthermore, it can be seen that the initial low resistance value is maintained even after a severe cooling test, and that high reliability can be imparted.

1A, 1C Wiring board (front and back not conducting)
1B, 1D wiring board (after front and back conduction)
2 Synthetic resin film base material 3 Conductor layer 4 Conductor layer 5 Ultrasonic bonding tool 5a Protrusion part 6 Ultrasonic bonding tool C Conducting part P Planned conduction position

Claims (8)

  In a wiring board in which a conductor layer constituting a wiring pattern is formed on the front and back surfaces of a synthetic resin film substrate, when electrically connecting a part of the wiring pattern between the front and back, a conduction scheduled portion is paired with a pair of ultrasonic waves. By pinching from both sides of the wiring board with a bonding tool, the synthetic resin present between the conductor layers of the part to be conducted is pushed away to the peripheral side to bring the front and back conductors into contact with each other. A wiring board front-and-back conduction method characterized by bonding by ultrasonic vibration from an ultrasonic bonding tool.   2. The wiring board according to claim 1, wherein when the planned conduction part is pinched, the conductive part is clamped from both sides of the wiring board while performing ultrasonic vibration with a pair of ultrasonic bonding tools. Conduction method.   The front-and-back conduction method of a wiring board according to claim 1 or 2, wherein a protrusion is provided on at least one of the opposing surfaces of the pair of ultrasonic connectors.   A protrusion is provided on only one of the opposing surfaces of the pair of ultrasonic connectors, and the thickness of the conductor layer on the side where the ultrasonic connector having the protrusion is in contact with The front and back conduction method of a wiring board according to claim 1 or 2, wherein the conductive board is set to be larger than the thickness of the conductor layer.   A protrusion is provided on only one of the opposing surfaces of the pair of ultrasonic connectors, and the thickness of the conductor layer on the side where the ultrasonic connector having the protrusion is in contact with The front and back conduction method of the wiring board according to claim 1, wherein the conductive board is set to be smaller than the thickness of the conductor layer.   The conductor layer is made of an aluminum foil having a thickness of 7 to 50 μm, the clamping pressure is set to 0.01 to 1 MPa, and the ultrasonic energy per protrusion of the ultrasonic connector is set to 0.01 to 100 J. The front-and-back electrical connection method of the wiring board of any one of Claims 1-5.   The conductor layer is made of a copper foil having a thickness of 7 to 50 μm, the clamping pressure is set to 0.01 to 1 MPa, and the ultrasonic energy per protrusion of the ultrasonic connector is set to 0.01 to 100 J. The front-and-back electrical connection method of the wiring board of any one of Claims 1-5.   The front and back conduction method of a wiring board according to any one of claims 1 to 7, wherein the synthetic resin film base material is made of polyethylene terephthalate or polyethylene naphthalate having a thickness of 20 to 50 µm.

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