Josep Altet
Universitat Politècnica de Catalunya – Barcelona Tech, Electronic Engineering Department

“Temperature measurements to enhance test and yield of mixed signal integrated circuits”

Measuring the temperature in an integrated circuit is a classical strategy to enhance the observability to assert the status of a running circuit. For instance, short circuits caused by electromagnetic discharges or open circuits generated by electromigration change the power dissipated by the affected devices, modifying the thermal map at the circuit surface. These examples alter radically the topology of the circuit and usually provoke catastrophic effects on the circuit’s behavior. In this scenario temperature measurements are usually used in failure analysis to locate the damaged devices, to perform a circuit’s autopsy. Nowadays nanometric technologies are susceptible to a variety of effects that introduce non-catastrophic effects in circuits, but a time shifting of the circuit’s performance, eventually driving a circuit or system out of specifications. Examples are clear in RF transmitters, where if gain or central frequency of tuned amplifiers are degraded due aging, a transmitter might stop working within specs. This can be solved by replacing the damaged circuit, but as device degradation is not catastrophic, the original circuit can be re-tuned to specifications if bias is changed, reducing waste and enhancing sustainability. This strategy requires the presence of sensors within the circuit that continuously monitor the performance of circuits and adjust its operation. In this talk I will present the research we are performing in order to be able to monitor the performance of RF circuits by using temperature measurements, built-in sensors as well as off chip measuring techniques.