| abstract |
The object of the present invention is to achieve a wiring substrate for the purpose of high frequency which maintains an excellent characteristic of high frequency and ensures high adherence reliability between a conductor layer and an insulation layer. A wiring substrate 10 is formed by alternatively laminating an insulating layer and a conductor layer on a laminated portion at an upper and a lower of a core substrate 20, a silane-coupling treatment is applied as a surface modifying treatment on signal wiring layers 42, 43 within the conductor layer of the laminated portion, and each signal wiring SL has a flat face. On one hand, surfaces of the other conductor layers 40, 41, 44, and 45 of the laminated portion on which a roughening treatment is applied become roughened surfaces. By such structure, when transmitting a high frequency signal to the signal wiring layers 42, 43 of the wiring substrate 10, since the signal wiring SL has the flat face, the increase of the conductor loss caused by a skin effect can be prevented, and the adherence reliability between the insulation layers 32, 33 are ensured by chemical bonding resulted from the silane-coupling treatment could be sufficient secured. |