Abstract: A flexible wiring board for double side connection is capable of improving the reliability of connection to circuit boards and a manufacturing process thereof. The flexible wiring board for double-side connection includes a polyimide film having a through-hole at a given location and first and second electrodes, one of which is provided on each side of the polyimide film. The second electrode closes one end of the through-hole in the polyimide film, such that any anisotropic adhesive used to connect an electric component to the first electrode will not flow through the through-hole to the other side of the polyimide film. The first and second electrodes are electrically connected each other by a plating layer.

Abstract: A board piece 2 of the present invention comprises a non-thermoplastic resin film 11, a thermoplastic resin film 10 formed on the non-thermoplastic resin film 11 and a metal wiring 8 formed on the surface of the thermoplastic resin film 10. Metal wiring 8 is partially exposed on board piece 2 to form a contact 12. A low-melting metal coating 13 is formed on contact 12 and two board pieces 2a, 2b are pressed against each other under heating with contacts 12a, 12b thereof being in contact with each other so that thermoplastic resin films 10a, 10b soften to adhere board pieces 2a, 2b to each other and low-melting metal coatings 13a, 13b melt and then solidify to connect contacts 12a, 12b to each other. The region of metal wiring 8 not used for connection is wiring 17 connecting contacts 12 to each other and a cover film 19 can be provided on the surface thereof. Contacts 12a, 12b can also be connected by applying ultrasonic wave.

Abstract: A board piece 2 of the present invention comprises a non-thermoplastic resin film 11, a thermoplastic resin film 10 formed on the non-thermoplastic resin film 11 and a metal wiring 8 formed on the surface of the thermoplastic resin film 10. Metal wiring 8 is partially exposed on board piece 2 to form a contact 12. A low-melting metal coating 13 is formed on contact 12 and two board pieces 2a, 2b are pressed against each other under heating with contacts 12a, 12b thereof being in contact with each other so that thermoplastic resin films 10a, 10b soften to adhere board pieces 2a, 2b to each other and low-melting metal coatings 13a, 13b melt and then solidify to connect contacts 12a, 12b to each other. The region of metal wiring 8 not used for connection is wiring 17 connecting contacts 12 to each other and a cover film 19 can be provided on the surface thereof. Contacts 12a, 12b can also be connected by applying ultrasonic wave.

Abstract: The present invention provides a flexible wiring board for double-side connection capable of improving the reliability of connection to circuit boards and a manufacturing process thereof.

Abstract: A board piece 2 of the present invention comprises a non-thermoplastic resin film 11, a thermoplastic resin film 10 formed on the non-thermoplastic resin film 11 and a metal wiring 8 formed on the surface of the thermoplastic resin film 10. Metal wiring 8 is partially exposed on board piece 2 to form a contact 12. A low-melting metal coating 13 is formed on contact 12 and two board pieces 2a, 2b are pressed against each other under heating with contacts 12a, 12b thereof being in contact with each other so that thermoplastic resin films 10a, 10b soften to adhere board pieces 2a, 2b to each other and low-melting metal coatings 13a, 13b melt and then solidify to connect contacts 12a, 12b to each other. The region of metal wiring 8 not used for connection is wiring 17 connecting contacts 12 to each other and a cover film 19 can be provided on the surface thereof. Contacts 12a, 12b can also be connected by applying ultrasonic wave.

Abstract: This invention provides a specially-shaped, double-face flexible printed wiring board having a small pitch at a high production yield. Metal wirings 22 and 32 formed on a base film 21, 31 of two elemental pieces 20 and 30 of a flexible printed wiring board are arranged in such a manner as to face each other while sandwiching a bonding film 16 not containing conductive particles between them, and are heat-pressed to each other. The adhesive resin film 16 so softened is pushed aside from the metal wirings 22 and 32 and the low melting point metal coating films 23 and 33 formed on the surface of the metal wirings 22 and 32 come into direct contact with each other and are fused. In this instance, the softened adhesive resin film 16 is charged between the metal wirings 22 and 32. Therefore, the molten low melting point metal does not scatter. The base films 21 and 31 are bonded by the adhesive resin film 16.