| 摘要 |
A wiring circuit board is provided, in which a circuit wiring is substantially free from a softening phenomenon which may otherwise occur due to heat over time, and is highly durable, less brittle and substantially free from cracking. The wiring circuit board includes a substrate comprising an insulative layer, and a circuit wiring provided on the insulative layer of the substrate. The circuit wiring has a layered structure including at least three copper-based metal layers. A lowermost one and an uppermost one of the copper-based metal layers each have a tensile resistance of 100 to 400 MPa at an ordinary temperature, and an intermediate copper-based metal layer present between the lowermost layer and the uppermost layer has a tensile resistance of 700 to 1500 MPa at the ordinary temperature.
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