Process for detecting the presence of a passivation over an integrated circuit

摘要

The detection circuit has a pulse generator, which has a counter incrementing the pulse length of each pulse sent out. The pulse (Se) is applied to the integrated circuit via a snake shaped metallising line (2). The line forms a pass band filter with the passivation layer, and thus the short pulses are not received at the receiver (Sd) whilst longer pulses are. A correctly passivated integrated circuit can thus be determined from a tolerance threshold around the critical cut off pulse lengths.