Audio coding and decoding

摘要

The present invention provides a circuit board in which peeling strength is prevented from decreasing and connection resistance to conductive material is prevented from increasing, though the contact area decreases when the circuit board has a copper foil. This circuit board has metal film (105) for covering a through hole on at least one surface of insulating substrate (101) having the through hole filled with conductive material (104). Uneven layer (1069 with a thickness of 5 mum or more is formed on a surface of metal film (105), and a metal layer is formed on the opposite surface to uneven layer (106).