WIRING BOARD AND MANUFACTURING METHOD THEREFOR

PROBLEM TO BE SOLVED: To provide a wiring board capable of suppressing warpage and swell that occur due to heat history even if the wiring board has a thin core substrate. SOLUTION: The build-up wiring board comprises: a core substrate 24 having a first via 23 that is filled with a conductive paste 22 for making interlayer connection in via holes that are formed on an insulating layer 21; and a build-up layer 26 that is formed on at least one surface of the core substrate 24 and that is formed with a second via 25 for making interlayer connection. The core substrate 24 is constituted of a resin composite insulating material containing a core material made of an organic fiber or an inorganic fiber, and has a thickness of 200 μm or less. The build-up layer 26 has a thickness equal to or larger than a minimum thickness that assures interlayer insulation, and is constituted of a film-shaped resin insulating material. COPYRIGHT: (C)2008,JPO&INPIT