| 摘要 |
PROBLEM TO BE SOLVED: To realize a multi-layer board in which the change in a characteristic impedance caused by micro via-holes is reduced. SOLUTION: In the multi-layer board 10 in plural layers of which a strip line or a microstrip line is formed, the width of a conductor path in micro via-holes 121, 131 used to interconnect signal lines 21, 22 formed in different layers, that is, the circumferential length of each of the micro via-holes 121, 131 is formed nearly equal to a width (w) of the signal lines 21, 22. Thus, the characteristic impedance of the micro via-holes 121, 131 is made almost equal to the characteristic impedance of the signal lines 21, 22 so as to improve the transmission and reflection characteristic of a signal. |
