| 摘要 |
PURPOSE:To enable a blind viahole to be easily and accurately formed preventing cuttings from staying in it by a method wherein an insulating layer whose main component is organic is laminated on a board, and then a blind hole is provided through YAG laser. CONSTITUTION:A copper plated laminar board where inner layer circuits 2 are built is employed as a board 1. A film whose main component is epoxy resin and synthetic rubber is laminated on both the sides of the board 1 and hardened by heating into an insulating layer 3. After the insulating layer 3 is formed, an adhesive agent layer 4 is provided thereon. A through-hole 5 is bored in the board 1 penetrating it by a drill. A blind viahole 6 is provided penetrating both the insulating layer 3 and the adhesive agent layer 4. Thereafter, a plating resist layer 7 is formed on the surface of the adhesive agent layer 4. Then, a circuit 8 is formed through an electroless copper plating method. As the blind viahole 6 is formed through YAG laser, it is accurately formed without producing cuttings. |
