Imp act of MCM technology on high speed transient waveforms

The impact of MCM technology material system properties on high speed logic transient waveshapes is examined. The analyses utilize a custom FFT-based transient simulation approach. The frequency-dependent complex propagation constant and line characteristic impedance in the presence of arbitrary losses are derived from the dispersion-corrected effective permittivity, impedance, conductor and dielectric losses for the particular transmission line and material properties under consideration. Conductor AC skin effect, and substrate ohmic loss due to finite conductivity are considered as well as the conductor bulk DC resistance and dielectric loss tangent (frictional dipole damping). Examples assume an ideal microstrip geometry in approximation to actual MCM surface line structures. The pulse performance is predicted for isolated discontinuity-free straight lines without nearby lines, vias, pins or package metallization in order to assess material property-related effects.