| 摘要 |
PURPOSE:To obtain a multilayer printed wiring board which is high in density, free of constraint in impedance characteristics, and controllable in evenness and interlaminar thickness by a method wherein an insulting board provided with a through-hole whose inner wall contains a catalyst, a catalyst bearing insulating layer formed of catalyst bearing prepregs, and a conductor layer formed through an electroless plating including a catalyst adsorbed part are provided. CONSTITUTION:A mask 9 is removed by an organic solvent, and then a multilayered board 7 is subjected to a copper electroless plating to form a conductor layer 11 on both the front and the rear side of the board 7 and the inner walls of through-holes 8a and 8b. In this case, concerning the through-hole 8a, the conductive layer 11 is formed only on a catalyst bearing insulating layer 6 and not formed on a catalyst free insulating layer 2, so that the conductor layer 11 is separated at the inner wall of the through-hole 8a and a conductor circuit pattern 1 and an outer copper layer 3 are connected together, on the other hand, concerning the through-hole 3b, the conductor layer 11 is formed on all the inner wall through the previously adsorbed catalyst. Then, an outer most circuit is formed through a photoprinting method, whereby a multilayer printed wiring board 14 provided with a divided viahole 12 and a normal through-hole 13 can be obtained. |
