Electrical properties of low-inductance barium strontium titanate thin film decoupling capacitors

Very low inductance capacitors using barium strontium titanate (BST) based thin film have been developed for use in decoupling applications for GHz LSI operations. Increasing clock frequency and integration density of high performance logic LSI such as CPU requires very low power line impedance over wide frequency ranges up to GHz order. BST thin film capacitors are promising for GHz LSI applications due to excellent electrical properties of low inductance and high capacitance. Low temperature sputter deposited BST thin films show high capacitance and good leakage properties. The fabricated thin film chip capacitors of 150 μm bump pitch show low equivalent series inductance (ESL) of 17 pH and low ESR of 0.05 Ω. Impedance of the chip capacitor at 1 GHz is 100 times lower than conventional multilayered ceramic capacitors (MLC). These results indicate that developed capacitors are suitable for the decoupling applications to GHz LSI operation.