THIN-FILM PULSE-PROPAGATION ANALYSIS USING FREQUENCY TECHNIQUES

High-speed pulse (rise time = 100 ps) propagation in a thin-film multichip package is analyzed in this paper. The thin-film lines were assumed to be 8 mu-m wide, 4 mu-m thick, 12 mu-m above the ground, and made of copper embedded in a dielectric medium with a dielectric constant of 3.5 (e.g., polyimide). Weeks' algorithm was 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. We have assumed that the dielectric imperfection and the conductor surface roughness are negligible for this study. An inverse fast Fourier transform (FFT) algorithm was employed to obtain the time-domain results. Line lengths studied ranged from 1 to 15 cm, and three types of terminations were treated: parallel, series, and open. Termination strategy for different line lengths is presented first. 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.