Abstract: A double-sided flexible printed board is manufactured by: (a) forming a polyimide precursor layer on a metal layer; (b) forming an upper circuit layer on the polyimide precursor layer by a semi-additive technique; and (c) imidating the polyimide precursor layer to form a polyimide insulating layer.

Abstract: A flexible wiring board are formed by growing metal bumps using a mask film patterned by photolithography. Fine openings can be formed with good precision, therefore, fine metal bumps can be formed with good precision because laser beam is not used to form opening in a polyimide film. After metal bumps have been formed, the mask film is removed and a liquid resin material is applied and dried to form a coating, which is then cured into a resin film. The coating can be etched at surface portions during coating stage to exposed the tops of metal bumps.

Abstract: Some embodiments of the invention cover the top of a flip chip IC with a conductive adhesive material. This material is used in place of a shielding metal can or plate in some embodiments, while it is used in conjunction with such metal can or plate in other embodiments of the invention. Also, some embodiments use a printing technique to coat the top of the flip chip with the conductive adhesive material. In some embodiments, the coating material is a silver paste.

Abstract: The multilayer flexible wiring board includes first and second patterned wiring layers, a resin film interposed between a surface of the first wiring layer and a surface of the second wiring layer, and a bump connected to the surface of the second wiring layer. The resin film is adapted to form an opening when the bump is forced into the resin film and an ultrasonic wave is applied to the bump. The bump is left in the opening to electrically connect the top of the bump to the first wiring layer.

Abstract: Some embodiments of the invention cover the top of a flip chip IC with a conductive adhesive material. This material is used in place of a shielding metal can or plate in some embodiments, while it is used in conjunction with such metal can or plate in other embodiments of the invention. Also, some embodiments use a printing technique to coat the top of the flip chip with the conductive adhesive material. In some embodiments, the coating material is a silver paste.

Abstract: The present invention pertains to a multilayer flexible wiring board. The multilayer flexible wiring board including first and second patterned wiring layers, a resin film interposed between a surface of the first wiring layer and a surface of the second wiring layer, and a bump connected to the surface of the second wiring layer, wherein the resin film is adapted to form an opening when the bump to force into the resin film and an ultrasonic wave is applied to the bump and the bump is left in the opening to electrically connect the top of the bump to the first wiring layer.

Abstract: The present invention pertains to a multilayer flexible wiring board. The multilayer flexible wiring board including first and second patterned wiring layers, a resin film interposed between a surface of the first wiring layer and a surface of the second wiring layer, and a bump connected to the surface of the second wiring layer, wherein the resin film is adapted to form an opening when the bump to force into the resin film and an ultrasonic wave is applied to the bump and the bump is left in the opening to electrically connect the top of the bump to the first wiring layer.

Abstract: A process for manufacturing a flexible wiring board according to the present invention comprises growing metal bumps 16 using a mask film patterned by photolithography. Fine openings can be formed with good precision, therefore, fine metal bumps 16 can be formed with good precision because laser beam is not used to form openings in a polyimide film. After metal bumps 16 have been formed, the mask film is removed and a liquid resin material is applied and dried to form a coating, which is then cured into a resin film. The coating can be etched at surface portions during coating stage to expose the tops of metal bumps 16.

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 bumpless ultrasonic bonding of flexible wiring board pieces. A metal coating 26 is formed on the surface of a contact region 181 of a metal wiring 28 of each of two flexible wiring board pieces 10, 30 and ultrasonic wave is individually applied by an ultrasonic resonator 45 to the contact regions 181 in contact with each other. The metal coatings 26 are bonded to form a multilayer flexible wiring board 50. The bumpless process eliminates any plating step for forming bumps without being influenced by non-uniformity bump height. A thermoplastic resin film 33 may be formed on the surface of one flexible wiring board piece 30 to bond flexible wiring board pieces 10, 30 by the adhesion of the resin film 33.

Abstract: In a flexible printed wiring board obtained by connecting metal bumps of a first flexible printed wiring part and connection pads of a second flexible printed wiring part, the first flexible printed wiring part is composed of a conductive layer and insulating layer adjacent thereto, holes A being provided in the insulating layer so as to reach the conductive layer, metal plugs being formed in these holes by an electrolytic plating method, metal bumps being produced by making the tips of these metal plugs project from the insulating layer. In this way, as many as possible flexible printed wiring boards can be obtained from a laminated sheet for flexible printed wiring of prescribed size.

Abstract: A double-sided flexible printed board is manufactured by the following steps of:

Abstract: Against a first resin film formed on a first metal film are pressed bumps on a second metal film so that the bumps are embedded into the first resin film. Either one of the first metal film or the second metal film or both is (are) patterned while the bumps are in contact with the first metal film, and the first resin film is heat-treated while the top of the first resin film is partially exposed to discharge the solvent or moisture from the exposed zone, and cure the first resin film. After curing, the bumps and the first metal film may be ultrasonically bonded to each other. A second resin film and a third metal film may be further layered to form a multilayer structure.

Abstract: The present invention aims to connect metal films without forming any opening in a resin film. Against a first resin film 16 formed on a first metal film 12 are pressed bumps 21 on a second metal film 11 so that the bumps 21 are embedded into the first resin film 16. Either one of the first metal film 12 or the second metal film 11 or both is (are) patterned while the bumps 21 are in contact with the first metal film 12, and the first resin film 16 is heat-treated while the top of the first resin film is partially exposed to discharge the solvent or moisture from the exposed zone and cure the first resin film 16. After curing, the bumps 21 and the first metal film 12 may be ultrasonically bonded to each other. A second resin film and a third metal film may be further layered to form a multilayer structure.

Abstract: A flexible printed wiring board constructed by using elemental pieces at a low cost. The elemental pieces 81a to 81c according to the present invention are provided respectively with supporting films 24a to 24c on one face and adhesive resin films 19a to 19c on the other face. The supporting films 24a to 24c have connecting openings on the bottom face of which the surface of metal wiring circuits are exposed as lands 23a to 23c. On the other hand, conductive bumps 16a to 16c, which are connected respectively to the metal wiring circuits 14a to 14c, project on the resin films 19a to 19c. To construct a flexible printed wiring board 83 by using plural elemental pieces 81a to 81c, the tips of the conductive bumps 16b and 16c are brought into contact respectively with the lands 23a and 23b on the bottom face of the openings and contact-bonded under heating. Thus, the elemental pieces 81a to 81c are adhered to each other owing to the adhesiveness of the resin film 19b and 19c.

Abstract: A double-sided flexible printed circuit board is manufactured by the following steps of: (a) forming a polyimide precursor layer on a first metal layer; (b) forming a second metal layer on the polyimide precursor layer; (c) patterning the second metal layer to form a second circuit layer or (c′) patterning the first metal layer to form a first circuit layer; and (d) imidating the polyimide precursor layer to form a polyimide insulating layer. The polyimide precursor layer is obtained by dissolving a polyamic acid or other polyimide precursor in N-methyl-2-pyrrolidone or the like and applying the resultant varnish to the first metal layer. The polyimide layer is then dried. The imidation ratio of the dried polyimide precursor layer is prevented from exceeding 50%.

Abstract: A process for manufacturing a flexible wiring board according to the present invention comprises growing metal bumps 16 using a mask film patterned by photolithography. Fine openings can be formed with good precision, therefore, fine metal bumps 16 can be formed with good precision because laser beam is not used to form openings in a polyimide film. After metal bumps 16 have been formed, the mask film is removed and a liquid resin material is applied and dried to form a coating, which is then cured into a resin film. The coating can be etched at surface portions during coating stage to expose the tops of metal bumps 16.

Abstract: A flexible wiring board according to the present invention comprising growing metal bumps 16 using a mask film patterned by photolithography. Fine openings can be formed with good precision, therefore, fine metal bumps 16 can be formed with good precision because laser beam is not used to form opening in a polyimide film. After metal bumps 16 have been formed, the mask film is removed and a liquid resin material is applied and dried to form a coating, which is then cured into a resin film. The coating can be etched at surface portions during coating stage to exposed the tops of metal bumps 16.

Abstract: The present invention pertains to a multilayer flexible wiring board.

Abstract: (a) A method of manufacturing a magnetic head suspension includes a polyimide precursor layer 2 that is formed over a springy material layer 1, (b) a metal layer 3 for lines is formed over the polyimide precursor layer 2, (c) the metal layer 3 is patterned by the subtractive process to produce lines 4, (d) the polyimide precursor layer 2 is patterned by a photolithographic technique to give the configuration corresponding to a polyimide insulating base layer 5, (e) the patterned polyimide precursor layer 2 is imidated to produce the polyimide insulating base layer 5, and (f) a cover coat layer 6 is formed over the lines 4.