Abstract
We have developed a new technique of adjusting propagation delay time of Multi-Wire Boards (MWBs) . MWBs use polyimide insulated copper wires for signal connection. The wires will intersect each other. Therefore, in high-density wiring, improper variation in the delay time will be caused by intersections of wires, adjacent through holes, folded wires, and via holes in the middle of wiring. A new estimation method was proposed and the influence of these factors on the variation of the delay time was investigated. It was found that about 73% of the variation is caused by the intersection of wires. With this new technique, it is possible, after finishing the routing design, to control the length of the wiring, and adjust the propagation delay time so that it is equal to that calculated by a newly developed software. We confirmed that the variation time of the boards designed in this way decreases to one-third or less of that of the conventional MWBs.
