| 摘要 |
PROBLEM TO BE SOLVED: To provide a multilayer printed wiring board of superior migration resistance. SOLUTION: In this multilayer printed wiring board, a plurality of internal layer 11 wherein a wiring pattern 12 is formed by etching a copper foil are laminated with prepreg 14 between the plates, in addition, external layer copper- plated plates or external layer copper foils 16 are put on both surfaces thereof with prepregs 15 in between, to mold into a body. In this case, by using a copper foil whose process leg is shorter than 5μm and a prepreg wherein a cross section forms of a glass cloth of a base material is flat, the minor axis/major axis ratio is 0.75 or below, and the glass cloth is made thin and an applied resin amount is increased so that a thickness of the glass cloth becomes 85% or below of the thickness after prepreg molding, contact of a circuit to the glass cloth filament is suppressed. |
