Minimization of via count in multiple-metal inductors performance characterization and physical modelling

High Q on-chip inductors are vital for modern RF ICs. A proven method of Q-enhancement is to use multiple metals stacked in a shunt manner, with a dense array of vias. The impact of fewer vias has not been investigated before. Here, we show that the same Q can be achieved with significantly fewer vias, thus simplifying the inductor layout. The traditional and new approaches are explained and physical models developed which give excellent agreement between simulations and measurements up to 6GHz