| 摘要 |
PROBLEM TO BE SOLVED: To have durability in response to superfining of a circuit and requirements of precision as a wiring board such as a package, etc., to which a semiconductor element is mounted. SOLUTION: In a multilayered wiring board 1 in which there are stacked in a multilayer an insulation layer 2 composed of a composite material mixing uniformly an inorganic filler with organic resin; and a conductive circuit 3 composed of a low resistance metal, the coefficient of thermal expansion of an insulation layer 4 of an outermost layer is smaller than that of an internal insulation layer 5. For instance, inorganic filler contents of low thermal expansion in the insulation layer 4 of an outenrmost layer are larger than that in the internal insulation layer 5, preferably the coefficient of thermal expansion of the outermost layer at room temperature to 250 deg.C is controlled to be 10 to 60×10<-6> / deg.C and the internal insulation layer 30 to 100×10<-6> / deg.C. Further, a semiconductor element is mounted onto an upper face of the insulation layer 4 of an outermost layer. |
