Flexible wiring board, an intermediate product of a flexible wiring board, and a multi-layer flexible wiring board
AssigneeSony Chemicals Corp.
InventorMasanori Takeuchi
Life of this patent
Estimating the term…
Abstract
The flexible wiring board has a first wiring film and a second wiring film. Because the first wiring film has a larger thickness than the second wiring film, the sectional area and electrical resistance of the first wiring film can be enlarged because of the larger film thickness even in a case where the first and second wiring films have almost the same width. Therefore, a high current can flow through the first wiring film, although the wiring film has a small width. As a result, a high density of the flexible wiring board can be easily achieved.
Claims13
A flexible wiring board having:
- a first resin film;
- a first wiring film, a bottom face of which is embedded into the first resin film;
- and
- a second wiring film, a bottom face of which is in contact with a surface of the first resin film.
The intermediate product of a flexible wiring board having a first resin film, and a metal foil wherein the metal foil has a thin film part and a thick film part connecting to the thin film part,
- the thick film part has a larger thickness than a thickness of the thin film part and is connected to the thin film part,
- a surface of the metal foil is flush,
- a part of a bottom face of the metal foil, where the thick film part is disposed, is embedded into the first resin film,
- a part of the bottom face of the metal foil, where the thin film part is disposed, is in contact with a surface of the first resin film, and
- the first resin film has a flat surface in an opposite side to where the metal foil is disposed.
A multi-layer flexible wiring board comprising a first flexible wiring board and a second flexible wiring board connecting each other, wherein
- the first flexible wiring board having:
- a first resin film;
- a first wiring film, a bottom face of which is embedded into the first resin film;
- a second wiring film, a bottom face of which is in contact with a surface of the first resin film;
- a second resin film formed on a surface of the first wiring film and a surface of the second wiring film, and
- at least one first opening is formed in a part of the second resin film where the first wiring film is disposed,
- at least one second opening is formed in a part of the second resin film where the second wiring board comprises a base film, and a wire on the base film,
- wherein a face of the second flexible wiring board at a side where the wire is disposed is located toward a face of the first flexible wiring board at a side where the second resin film is disposed,
- a first bump is arranged in the first opening,
- the wire of the second flexible wiring board is connected to the first wiring film by the first bump,
- a second bump is arranged in the second opening,
- the wire of the second flexible wiring board is connected to the second wiring film by the second bump.
Dependencies are inferred from the claim text.