Thin-film pulse propagation analysis using frequency techniques

High-speed pulse (rise time=100 ps) propagation in a thin-film multichip package is analyzed. The thin-film lines are assumed to be 8 μm wide, 4 μm thick, 12 μm above the ground, and made of copper embedded in a dielectric medium with a dielectric constant of 3.5 (e.g., polyimide). Weeks´ algorithm is used to calculate the wideband line characteristics which include the skin effect of conductors and the proximity effect of the ground up to a frequency of 10 GHz. It is assumed that the dielectric imperfection and the conductor surface roughness are negligible. An inverse fast Fourier transform (FFT) algorithm is used to obtain the time-domain results. Line lengths studied ranged from 1 to 15 cm. and three types of terminations are treated: parallel, series, and open. Termination strategy for different line lengths is presented. The maximum line length allowable in the thin-film conductor system is then examined. Finally, crosstalk at various locations of the quiet lines with different terminations is discussed