Simulating frequency-dependent current distribution for inductance modeling of on-chip copper interconnects
Proceedings of the 2000 international symposium on Physical design - ISPD '00
500+ MHz designs using deep-submicron (DSM) copper interconnects require accurate and efficient modeling of cladding-metals' frequency-dependent impedance . In this paper, for the first time, we simulate and describe the current distribution inside a copper-based interconnect in a rich set of multi-line structures. The difference of the resistivities of copper alloy and the cladding metals causes a non-monotonic current density versus cross-wire axis relation. The same situation does not
... uation does not occur for the state-of-the-art aluminum processes. It enlarges the inductance by more than 12 percent. Simulating the frequency dependence of the inductance with this property, we find that PEEC  can simulate cladded wire profile to achieve accurate inductance extraction. Other approximate methods result in inaccurate and lower inductance values. A new modeling methodology based on library look-up is then proposed to make an efficient field-solver based extraction flow for realistic DSM designs. KEYWORDS Copper interconnect, skin-effect current distribution, cladding material, electromagnetic field solvers.