MANUFACTURE OF MULTILAYER PRINTED BOARD

PROBLEM TO BE SOLVED: To improve the solder heat resistance and productivity in the process of manufacturing a multilayer printed board, using prepreg sheets which easily absorb moisture esp., in manufacturing steps among circuit boards used for various electronic apparatuses by setting the moisture absorption below 1.5 wt.% in a hot press step. SOLUTION: In a batch-type drying furnace aramide-epoxy sheets 1a, 1b and a double-sided circuit board 10 are dried. On a laminate plate 6a a metal foil 5b, an aramide-epoxy sheet 1b, a circuit board 10, an araminde-epoxy sheet a, a metal foil 5a and a laminate plate 6b are positioned and laminated in an environment of 35 deg.C, 30%RH, charged in a controlled environment ordinarily of 25 deg.C, 60%RH. The laminate with products mounted on the laminate plate 6a is set on a heat press and is hot pressed, thus obtaining a high solder heat resistance and superior productivity.