| 摘要 |
PURPOSE:To completely repair by chemical plating even if a through hole is partly cut and to guarantee high reliability by forming a dummy circuit in addition to a normal circuit on an inner layer circuit board of a position to be formed with a through hole, opening the hole, and chemically plating it. CONSTITUTION:An outer layer circuit board 22 for forming a predetermined circuit 21 by etching copper layers adhered to both side surfaces of a polyimide resin base material, and an inner layer circuit board 25 having a circuit and a dummy circuit 24 not to be operated as a circuit are press-bonded integrally through adhesive 26 made of polyimide resin to manufacture a multilayer circuit board 30. If through holes 28, 29 are formed at positions corresponding to through holes 37 of the layers 22, 25, drilling can be facilitated. After the holes 37 are formed, through hole plating 38 is formed by chemical plating. If the thickness of an insulating layer is less than 100mum, a plating layer having a through hole 38 of excellent quality is formed. |
