Thin film low inductance decoupling device for high speed digital circuits

This paper describes a thin film low inductance decoupling device (TLD), developed for high speed digital circuits. The increasingly faster edge rates of today´s high speed digital devices require high-performance decoupling capacitors to supply sufficient instantaneous local current, very low inductance, and low impedance at high frequencies. The TLD uses multi layered dielectric layers to achieve high capacitance and fine-pitch BGA terminals to achieve low inductance. Using a numerical implementation of the partial element equivalent circuit method to design the electrodes and terminals, and using a sputtering process to generate dielectric layers, (Ba,Sr)TiOx (k=700), capacitance and inductance values of 0.33 μF (6.6 μF/cm²) and under 20 pH (1 pH×cm²), respectively, were achieved.