| 摘要 |
A thin film multi-layer wiring substrate comprising a plurality of wiring layers, each adjacent pair of wiring layers being separated by an insulating layer, wherein at least one of the wiring layers includes wiring formed by an inner conductor member and a conductor layer surrounding the periphery thereof through an insulating material. A printed circuit board comprising a signal line conductor formed on a first insulating layer which selectively covers a first ground layer spreading on a substrate, shield walls extending across gaps on both sides of the signal line conductor, and conductively connected to the first ground layer, and a second ground layer conductively connected to the shield walls, stretching across gaps above the signal line conductor, and in which a plurality of openings having lengths and distances of equal to or less than one quarter of a frequency handled by the signal line conductor are formed, is also disclosed.
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