| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a multilayer printed wiring board which uses a laminated substrate of high external connection reliability, with no standing wave or reflection occurring at a through hole. SOLUTION: A through hole 66 of coaxial structure is used to prevent occurrence of standing wave and reflection, for a raised electric characteristics. A field via 160 is formed directly above the coaxial through hole 66, to shorten a wiring length and improve a high-frequency performance. Since a solder bump 76U is arranged on a flat field via, no void remains inside the solder bump, resulting in a higher reliability of the solder bump.</p> |
