| 摘要 |
PURPOSE:To realize sufficiently reliable connection through a through hole, by forming an electroless plated layer on the surface of a printed circuit board and on the sidewall of the through hole while rotating the board and circulating a plating solution through the through hole. CONSTITUTION:A printed wiring board 2 including an insulating board whose top and rear faces are coated with copper foil 6 is prepared. A through hole 1 is formed in the printed circuit board by means of a drill. The board is then dipped in an aqueous solution of electroless plating catalyst consisting of acid colloidal solution containing stannous chloride, palladium chloride and sodium chloride, so that the electroless plating catalyst 7 is deposited on the surface of the copper foils 6 on the board 2 and on the sidewalls of the through hole 1. The board is then dipped in an electroless copper plating solution, so that an electroless plated copper layer 8 is formed. Subsequently, a predetermined conductor circuit 9 is provided thereon by the photoetching process to complete the printed wiring board. In this manner, the uniformity in thickness of the plated layers can be improved substantially. |
