| 摘要 |
PROBLEM TO BE SOLVED: To raise the surge absorbing ability and make it sufficient without using a thin green sheet. SOLUTION: The wiring board 1 is composed of an alumina or glass ceramic board, etc., having at least two wiring layers on the board. Vias 13 are provided in the board 1 and filled with conductors 14, and a surge absorbing insulation layer 15 is provided on openings of the vias 13 so as to cover the conductors 14 and connected between outer input/output conductors and ground conductors. Thus, the surge absorbing insulation layer 15 can be easily made thin down to a desired thickness (of e.g. about 10-40μm) without using a thin green sheet, and hence the surge absorption ability can be raised. |
