Paul Huray, Professor, University of South Carolina
Olufemi Oluwafemi, Sr. Signal Integrity Engineer, Intel
Jeff Loyer, Signal Integrity Lead, Intel
Eric Bogatin, President, Bogatin Enterprises
Xiaoning Ye, Intel

Power loss caused by surface roughness of copper can more than double insertion losses in high speed serial interconnects. Empirical models of copper roughness are not accurate enough for data rates > 5 Gbps to assure signal integrity. A first principles electromagnetic model has been developed based on observed copper surface texture which accurately describes attenuation and dispersion of signals and its accuracy has been confirmed through simulations and measurements up to 40 GHz. One conclusion of this model is that the conventional description of RMS surface roughness is misleading, yielding inaccurate predictions and misinterpretations of how currents flow on interconnects.