| 摘要 |
<p>PROBLEM TO BE SOLVED: To suppress emission of high-frequency noise having substantially no effect on the high-frequency operation of signal lines by forming magnetic material between a power supply wiring layer and ground layers a so that the power supply wiring is covered with the magnetic material and forming insulating dielectric in the other portion. SOLUTION: A magnetic material 12 is formed on a power supply wiring layer 11 so that power lines are covered with the magnetic material, and two ground 13 is placed above and under thereof. Dielectric 17 is placed between the ground layers 13 and the power supply wiring layer 11. Further, signal wirings layers 14-16 are formed outside the ground layers 13 with the dielectric 17 in-between. As a result, high-frequency magnetic fields produced due to high-frequency current passed through the power lines are confined in the surrounding of the power lines, and thus effect on the surroundings is suppressed. Therefore, the impedance of the wiring can be enhanced.</p> |
