| 摘要 |
PROBLEM TO BE SOLVED: To improve connection reliability by forming an outer layer conductor at a temperature higher than Tg of conductive paste and at a temperature lower than Tg of an insulating layer apart from a process for stacking and integrating the insulating layer. SOLUTION: Copper foils are stuck to both faces of an insulating base material 11, unnecessary copper foil is selectively etched/removed, inner layer conductors 12 are formed and an inner layer circuit board 1 is obtained. An insulating adhesive layer 22 is stuck to one face of copper foil 21 and a tearable organic film 23 to the surface of an insulating adhesive layer 22, and a multilayer wiring material 2 is formed. Non-through holes 3 are made in the material 2 and the non-through holes 3 are filled with conductive paste 4, they are set to be a semi-curing state and a polyethylene telephthalate film is peeled off. The multilayer wiring board materials 2 are press-fixed to both sides of the inner layer circuit board 1 by heating them at a temperature higher than Tg of conductive paste 4 and a temperature lower than Tg of the insulating adhesive layers 22 so as form outer layer conductors 25. |
