A buffer circuit for reducing leakage current and for protecting circuits from electrostatic discharge. A source file repository stores a plurality of active source files belonging to a component. An entry in the split masked substitution tables is defined by selecting bits from the corresponding entry in the original masked substitution table, as masked by the corresponding one of the set of random value data words and by selecting bits from the corresponding one of the set of random value data words as masked by the mask value. The cathode terminal is provided with a through hole formed at a portion to be brought into contact with each of the capacitor elements.