A study of the high frequency performance of thin film capacitors for electronic packaging

The provision of adequate decoupling capacitance in the power distribution system for integrated circuits (ICs) is an increasing concern. As clock rates and the IC gate density increase, discrete chip capacitors do not satisfy the decoupling requirements for high current switching at very high frequencies. Thin film capacitors not only exhibit better high frequency performance than discrete ceramic capacitors, but also provide the possibility for passive component integration. In this work, the high frequency performance of thin film capacitors was investigated using Maxwell Eminence, a high frequency structure simulator based on the finite element method. Good agreement between the calculated impedance and experimental results was obtained. At high frequencies, the performance of thin film capacitors is related to contact configurations, dielectric and metal layer thicknesses, and capacitor shapes. The influence of these factors on the impedance behavior was examined. Equivalent circuits of a thin film capacitor for use in a circuit simulator at high frequencies are discussed.