Low-inductance decoupling capacitor for the thermal conduction modules of the IBM Enterprise System/9000 processors
by J. N. Humenik, J. M. Oberschmidt, L. L. Wu, S. G. Paull
Multilayer ceramic decoupling capacitors fabricated using a barium titanate-based dielectric are used with the glass-ceramic/copper/polyimide substrates of the thermal conduction modules (TCMs) of the IBM Enterprise System/9000 processors to suppress the voltage noise generated by the logic circuits of the semiconductor chips used in the processors. Use is made of thick-film multilayer ceramic fabrication processes and thin-film termination processes to achieve substrate-mounted capabilities which, when combined with the low-inductance design of the capacitors, minimize the inductance of the decoupling paths to their adjacent chips. When mounted on the glass-ceramic/copper/polyimide substrate of a water-cooled TCM, the capacitors suppress approximately 50% of the voltage noise, thereby enhancing the performance of the TCMs.