| 摘要 |
PROBLEM TO BE SOLVED: To provide a low-loss multilayered wiring board wherein a transfer loss, especially in a high-frequency band, is reduced. SOLUTION: A low-loss multilayered wiring board (multilayered wiring board) 1 having a substrate 2 of ceramics and a wiring board (multilayered wiring board) 3. The multilayered wiring board 3 has multiple laminated wiring layers, each of which comprises an insulating film 6 of polyimide resin of about thickness 25-50μm, a conductor film 7 formed in the planar direction of the insulating film 6, and a via conductor 8 of height 25-50μm for connecting the conductor films 7 above and below the insulating film 6 through the insulating film 6. Since especially, a material for the insulating film 6, such as of low water absorbance, coefficient of water absorption which is 0.3% or less under such a condition of 25 deg.C, 25% of relative humidity(RH), is used. Specifically, as a material of the insulating film 6, such a material with the coefficient of water absorption is set in a range of 0.04-0.06% under such condition as 25 deg.C, 25% relative humidity is used. |
