The invention concerns novel copper or silver complexes and their use for gas-phase chemical deposition of metal copper or silver almost free of impurities. A semiconductor chip is coupled to a stiff chip carrier, and there is no stiffener ring on a periphery of the chip carrier. Specifically, a number of continuous bad frames that occur currently is determined. In the method, at least one signal of at least one operating characteristic variable of the secondary air pump is determined during the determination of the signal characterizing the secondary air flow and a conclusion is drawn as to a fault in the secondary air system when the signal of the at least one operating characteristic variable lies outside of a pregiven interval.