PRODUCTION OF MULTILAYER PRINTED WIRING BOARD

摘要

PURPOSE:To enhance reliability in the connection of through hole plating while lowering coefficient of thermal expansion by employing a copper foil thinner than a specified value in an inner layer circuit of a multilayer printed wiring board. CONSTITUTION:Surface of a land 2 of an inner layer circuit 2 is subjected to copper plating 3 to set the total thickness at 25mum or above. Both-sided printed wiring boards and a surface circuit, i.e., a copper foil 5, are integrated through adhesive insulation layers 4 and then the surface circuit is processed. Subsequently, a through hole 6 is made and the wall face thereof is subjected to plating of 20mum thick thus conducting the surface circuit and the inner layer circuit.