Flexible wiring board
AssigneeNitto Denko Corporation
InventorsYasuo Nakatsuka, Yuichi Takayoshi, Chiharu Miyaake, Toshihiko Sugimoto
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Abstract
A flexible wiring board including a gold pad having dynamic Vickers hardness of not less than 50 or having a ratio of amount of nickel in a surface of the gold pad (atomic weight %) to thickness of gold (μm) of not more than 5 or having both the dynamic Vickers hardness of not less than 50 and the ratio of amount of nickel in the surface of the gold pad (atomic weight %) to thickness of gold (μm) of not more than 5, to provide a flexible wiring board that can substantially ensure the connection reliability when the board is connected with a semiconductor device by wiring bonding.
Claims7
A flexible wiring board including a base layer, a conductor layer provided on the base layer and a gold pad having a dynamic Vickers hardness of not less than 50 provided on the conductor layer, said gold pad comprising a gold layer provided on a nickel layer, the nickel layer having a thickness of 4-15 μm;
- and said base layer being reinforced with a reinforcing layer at an area corresponding to a position of the gold pad, an adhesive layer being interposed between the base layer and the reinforcing layer, said adhesive layer having a complex shear modulus (G*) of not less than 2.0×109 dyn/cm2 at 25 Hz at a temperature at which the gold pad is connected with wires by wire bonding.
A flexible wiring board including a gold pad comprising a gold layer provided on a nickel layer and having a ratio of an amount of nickel (atomic weight %) in a surface of the gold layer of the gold pad to thickness of the gold layer (μm) of not more than 5.
A flexible wiring board including a gold pad comprising a gold layer provided on a nickel layer and having a dynamic Vickers hardness of not less than 50 and a ratio of an amount of nickel (atomic weight %) in a surface of the cold layer of the gold pad to thickness of the gold layer (μm) of not more than 5.
Dependencies are inferred from the claim text.