Patent ID: 7105221

Claim:
A circuit board comprising a flexible film and a circuit pattern comprising a metal provided on the flexible film, wherein dimensional change rate of the circuit pattern is within ±0.01%, wherein the circuit board is made by a method comprising the steps of laminating the flexible film to a reinforcing plate with a self-stick, removable organic layer having a thickness of 5 μm or less; forming the circuit pattern; and peeling the flexible film off the reinforcing plate, and wherein the following condition is satisfied: A×B×C is in the range of 4.3×10 −6 to 4.3×10 −3 , where A is the peel strength (g/cm) of the flexible film to the self-stick, removable organic layer, B is the reciprocal (μm −1 ) of the thickness of the flexible film, and C is the reciprocal (mm 2 ) of the Young's modulus of the flexible film.