RF functional-based complete FA flow

The device under analysis is a frequency synthesizer, operating in the range of 2 GHz to 4 GHz, built in BiCMOS technology, failing on application at low temperature (− 36 °C). Fault Isolation step is based on the replication of functional failure mode, through application board as electrical stimulus to activate the fault. Moreover, since failure is depending on temperature and voltage conditions, a Dynamic analysis through Laser Stimulus has been implemented (DLS) with a RTVM-like approach. This setup required specific adaption of application board in order to cope with mechanical and electrical constraints of DLS while reproducing failure mode in the GHz range. The amplitude variation of failing RF output signal was monitored by an additional circuitry that converted information of loss of signal in a suitable logic signal for DLS analysis. Fault Isolation pointed out to specific high frequency bipolar transistors on a divider block. Physical Analysis addressed to these components, which are key for this kind of products, put in evidence dislocations inside Si-Ge layer.