Abstract: When connecting a semiconductor device such as an IC chip with a circuit board by the flip-chip method, a semiconductor device is provided without forming bumps thereon, which enables highly reliable and low cost connection between the IC chip and circuit board while ensuring suppressing short-circuiting, lowering connection costs, suppressing stress concentrations at the joints and reducing damage of the IC chip or circuit board. The bumpless semiconductor device is provided with electrode pads 2 on the surface thereof and with a passivation film 3 at the periphery of the electrode pads 2, and conductive particles 4 are metallically bonded to the electric pads 2. Composite particles in which a metallic plating layer is formed at the surface of resin particles are employed as the conductive particles 4.

Abstract: When connecting a semiconductor device such as an IC chip with a circuit board by the flip-chip method, a semiconductor device is provided without forming bumps thereon, which enables highly reliable and low cost connection between the IC chip and circuit board while ensuring suppressing short-circuiting, lowering connection costs, suppressing stress concentrations at the joints and reducing damage of the IC chip or circuit board. The bumpless semiconductor device is provided with electrode pads 2 on the surface thereof and with a passivation film 3 at the periphery of the electrode pads 2, and conductive particles 4 are metallically bonded to the electric pads 2. Composite particles in which a metallic plating layer is formed at the surface of resin particles are employed as the conductive particles 4.

Abstract: When connecting a semiconductor device such as an IC chip with a circuit board by the flip-chip method, a semiconductor device is provided without forming bumps thereon, which enables highly reliable and low cost connection between the IC chip and circuit board while ensuring suppressing short-circuiting, lowering connection costs, suppressing stress concentrations at the joints and reducing damage of the IC chip or circuit board. The bumpless semiconductor device is provided with electrode pads 2 on the surface thereof and with a passivation film 3 at the periphery of the electrode pads 2, and conductive particles 4 are metallically bonded to the electric pads 2. Composite particles in which a metallic plating layer is formed at the surface of resin particles are employed as the conductive particles 4.

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: An object of the present invention is to provide a simple process for manufacturing a flexible printed wiring board having fine metal bumps. A resin coating 21 and a resist film 24 are formed in this order on the surface of a metal film 11 and on the surface of each metal bump 16 formed on the metal film 11, and a pressure is applied on the surface to depress the resist film 24 on the metal bump 16, followed by etching. As the surface of the resin coating 21 is partially exposed at the depressed portion of the resist film 24, etching of the resin coating 21 proceeds from that portion to bulge the surface of the metal bump 16 from the resin coating 21. If the resist film 24 is formed after a flexible resin coating 22 is formed on the rigid resin coating 21, the flexible resin coating 22 can serve as an adhesive 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: When connecting a semiconductor device such as an IC chip with a circuit board by the flip-chip method, a semiconductor device is provided without forming bumps thereon, which enables highly reliable and low cost connection between the IC chip and circuit board while ensuring suppressing short-circuiting, lowering connection costs, suppressing stress concentrations at the joints and reducing damage of the IC chip or circuit board. The bumpless semiconductor device is provided with electrode pads 2 on the surface thereof and with a passivation film 3 at the periphery of the electrode pads 2, and conductive particles 4 are metallically bonded to the electric pads 2. Composite particles in which a metallic plating layer is formed at the surface of resin particles are employed as the conductive particles 4.

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: 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 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: 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 multilayer flexible wiring board, suited for mounting semiconductor elements. The flexible wiring board is fabricated in the following manner. A flexible wiring board piece having a metal wiring, in which a metal coating is exposed on at least a part of surface of the metal wiring, is adhered to another flexible wiring board piece having a metal projection on which a metal coating is formed. One of or both of the metal coatings on the metal wiring and the metal projection is composed of a soft metal coating a surface of which has a Vickers' hardness of 80 kgf/mm2 or lower. The metal coating of the metal wiring contacts with the metal coating of said metal projection and ultrasonic wave is applied thereto to connect the metal wiring with the metal projection.

Abstract: A process for manufacturing a flexible wiring board according to the present invention includes growing metal bumps (16) using a mask film patterned by photolithography. Fine openings are formed in a polyimide film with good precision allowing fine metal bumps (16) to be formed with good precision. 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 multilayer flexible wiring board, suited for mounting semiconductor elements. The flexible wiring board is fabricated in the following manner. A flexible wiring board piece having a metal wiring, in which a metal coating is exposed on at least a part of surface of the metal wiring, is adhered to another flexible wiring board piece having a metal projection on which a metal coating is formed. One of or both of the metal coatings on the metal wiring and the metal projection is composed of a soft metal coating a surface of which has a Vickers' hardness of 80 kgf/mm2 or lower. The metal coating of the metal wiring contacts with the metal coating of said metal projection and ultrasonic wave is applied thereto to connect the metal wiring with the metal projection.

Abstract: A multilayer flexible wiring board, suited for mounting semiconductor elements. The flexible wiring board is fabricated in the following manner. A flexible wiring board piece having a metal wiring, in which a metal coating is exposed on at least a part of surface of the metal wiring, is adhered to another flexible wiring board piece having a metal projection on which a metal coating is formed. One of or both of the metal coatings on the metal wiring and the metal projection is composed of a soft metal coating a surface of which has a Vickers' hardness of 80 kgf/mm2 or lower. The metal coating of the metal wiring contacts with the metal coating of said metal projection and ultrasonic wave is applied thereto to connect the metal wiring with the metal projection.

Abstract: An object of the present invention is to provide a simple process for manufacturing a flexible printed wiring board having fine metal bumps.

Abstract: An object of the present invention is to provide a simple process for manufacturing a flexible printed wiring board having fine metal bumps. A resin coating 21 and a resist film 24 are formed in this order on the surface of a metal film 11 and on the surface of each metal bump 16 formed on the metal film 11, and a pressure is applied on the surface to depress the resist film 24 on the metal bump 16, followed by etching. As the surface of the resin coating 21 is partially exposed at the depressed portion of the resist film 24, etching of the resin coating 21 proceeds from that portion to bulge the surface of the metal bump 16 from the resin coating 21.