Transmission characteristics of narrow line-width interconnections on silicon substrates

Loss and dispersion characteristics have been investigated for narrow-linewidth 5- mu m- and 1- mu m-wide Au/Cr microstrip structures on low- and high-resistivity semiconductor substrates. Low-resistivity silicon substrates with narrow microstrip lines exhibit large losses and moderate-to-excessive dispersion, which may render them undesirable for use in large-area, high-speed, VLSI circuits. Alternatively, high-resistivity silicon substrates were found to have significantly lower attenuation and nearly linear phase characteristics for 5- mu m linewidths over the 10-GHz frequency range considered. However, for 1- mu m linewidths the loss and dispersion characteristics for both high- and low-resistivity substrate microstrip lines may be problematic when used in digital and analog environments where maintaining waveform integrity is of key concern. The data presented should assist in the design and layout of high-speed, large VLSI chips which use small geometry interconnects.<>