Sony Chemicals Corporation

Sony Corporation

Sony Chemical & Information Device Corporation

Toshihiro Shinohara

Yutaka Kaneda

Keiichi Naito

Hideyuki Kurita

Masanao Watanabe

Soichiro Kishimoto

Mitsuhiro Fukuda

Yukio Anzai

Masahiro Watanabe

Keiichi Naitoh

An object of the present invention is to manufacture a bump-attached wiring circuit board with which stable bump connections are possible, and there is no need for bothersome operations such as plating pretreatments. A bump formation etching maskis formed on the bump formation sideof a metal foilhaving a thickness (t+t) equal to the sum of the thickness tof a wiring circuitand the height tof the bumpsto be formed on a wiring circuit, the bumpsare formed by half-etching the metal foilfrom the bump formation etching maskside down to a depth corresponding to a predetermined bump height t, and a metal thin film layercomposed of a different metal from the metal foilis formed on the bump formation side of the metal foil, thereby providing a bump-attached wiring circuit board with which stable bump connections are possible, and there is no need for bothersome operations such as plating pretreatments.

Method for manufacturing a bump-attached wiring circuit board

In the present invention, a reference conductive layer and a first surface conductive layer are respectively provided on a surface and a back face of a first base film. The first base film includes a first via hole penetrating the first surface conductive layer. After a first electroless plating layer and a first conductive material are sequentially grown on a surface of the first base film, a first coating conductive layer composed of the first electroless plating layer, the first conductive material and the first surface conductive layer, is etched to have a reduced thickness. Then, the first coating conductive layer is patterned to form a first wiring layer. In this manner, a desired pattern width can be obtained even in the case where the first coating conductive layer is patterned by isotropic etching such as wet etching.

Method of manufacturing flexible wiring board

An object of the present invention is to manufacture a bump-attached wiring circuit board with which stable bump connections are possible, and there is no need for bothersome operations such as plating pretreatments. A bump formation etching mask () is formed on the bump formation side () of a metal foil () having a thickness (t+t) equal to the sum of the thickness tof a wiring circuit () and the height tof the bumps () to be formed on a wiring circuit (), the bumps () are formed by half-etching the metal foil () from the bump formation etching mask () side down to a depth corresponding to a predetermined bump height tand a metal thin film layer () composed of a different metal from the metal foil () is formed on the bump formation side of the metal foil (), thereby providing a bump-attached wiring circuit board with which stable bump connections are possible, and there is no need for bothersome operations such as plating pretreatments.

Wiring circuit boards with bumps can be manufactured such that stable bump connections are possible and plating pre-treatments or other difficult operations are rendered unnecessary. By utilizing a technique whereby a bump-formation etching maskis formed on a bump-forming surfaceof a metal foilwhich has a thickness that is the sum of the thickness tof the wiring circuitand the height tof the bumpswhich are to be formed on the wiring circuit(tt), and then the bumpsare formed by half-etching the metal foilto a depth corresponding to the desired bump height tfrom the bump-formation etching maskside, wiring circuit boards with bumps can be manufactured such that stable bump connections are possible and plating pre-treatments or other complex processes are rendered unnecessary.

Method for manufacturing wiring circuit boards with bumps and method for forming bumps

A board pieceof the present invention comprises a non-thermoplastic resin film, a thermoplastic resin filmformed on the non-thermoplastic resin filmand a metal wiringformed on the surface of the thermoplastic resin film. Metal wiringis partially exposed on board pieceto form a contact. A low-melting metal coatingis formed on contactand two board piecesare pressed against each other under heating with contactsthereof being in contact with each other so that thermoplastic resin filmssoften to adhere board piecesto each other and low-melting metal coatingsmelt and then solidify to connect contactsto each other. The region of metal wiringnot used for connection is wiringconnecting contactsto each other and a cover filmcan be provided on the surface thereof. Contactscan also be connected by applying ultrasonic wave.

Board pieces, flexible wiring boards and processes for manufacturing flexible wiring boards

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

Board pieces, flexible wiring boards, and processes for manufacturing flexible wiring boards

Wiring circuit boards with bumps can be manufactured such that stable bump connections are possible and plating pre-treatments or other difficult operations are rendered unnecessary. By utilizing a technique whereby a bump-formation etching mask is formed on a bump-forming surface of a metal foil which has a thickness that is the sum of the thickness t of the wiring circuit and the height t of the bumps which are to be formed on the wiring circuit (t &plus;t ), and then the bumps are formed by half-etching the metal foil to a depth corresponding to the desired bump height t from the bump-formation etching mask side, wiring circuit boards with bumps can be manufactured such that stable bump connections are possible and plating pre-treatments or other complex processes are rendered unnecessary.

A bump formation etching mask is formed on the bump formation side of a metal foil having a thickness (t &plus;t ) equal to the sum of the thickness t of a wiring circuit and the height t of the bumps to be formed on a wiring circuit. The bumps are formed by half-etching the metal foil from the bump formation etching mask side down to a depth corresponding to a predetermined bump height t A metal thin film layer formed of a different metal from the metal foil is formed on the bump formation side of the metal foil, thereby providing a bump-attached wiring circuit board with which stable bump connections are possible, and there is no need for bothersome operations, such as plating pretreatments.

Bump-attached wiring circuit board and method for manufacturing same

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

Growing community of inventors

Kanuma, Japan

Toshihiro Shinohara