Circuit-forming substrate and circuit substrate

摘要

There are provided a circuit-forming substrate comprising a long stainless steel foil having formed on one surface or both surfaces thereof a polyimide resin layer wholly or partially, and a circuit substrate formed by using the circuit-forming substrate, wherein a conductor layer is finely patterned on the circuit-forming substrate. The circuit-forming substrate sufficiently satisfies low cost, high density and high reliability, scarcely causes warping of the substrate itself, and has excellent workability.