| 摘要 |
PROBLEM TO BE SOLVED: To provide a low thermal expansion printed wiring board with less warpage and less swell on the surface thereof. SOLUTION: A core substrate 1 of the printed wiring board is formed by laminating three or more resin layers 3 in which unidirectionally aligned fibers 4 are impregnated with resin 5. The resin layers 3 include: a first resin layer 3a disposed on the outermost layer of one primary surface side of the core substrate 1; a second resin layer 3b disposed on the outermost layer of the other primary surface side of the core substrate 1; and third resin layers 3c that are disposed in the center in the thickness direction of the core substrate 1 and that have fibers 4 aligned in a different direction from those of the fibers 4 of the first and second resin layers 3a, 3b, wherein the third resin layers 3c have more fibers per unit length than the first and second resin layers 3a, 3b. COPYRIGHT: (C)2008,JPO&INPIT |
