Rapid modeling and efficient characterization of shielded oval-shaped spiral inductors

A rapid CAD technique is presented for accurately modeling oval (stadium) shaped inductors with various shielding schemes, which features rapid simulation speed (in the range of few seconds per spiral) and significantly enhanced capacity compared to conventional electromagnetic simulation tools. Inaccuracies inherent in popular measurement and de-embedding methods are discussed and effectively factored out by using the proposed modeling approach to include polysilicon shield patterns and interconnect leads to the device model. The proposed technique is found to yield a model to measurement correlation averaging 2.9% in low frequency inductance and 3% in self-resonance frequency, for an array of inductors fabricated in an 180nm 5-metal CMOS process.