Method and apparatus to measure statistical variation of electrical signal phase in integrated circuits using time-correlated photon counting

摘要

Time-correlated photon counting is used to measure integrated circuit (IC) performance related to signal jitter (such as clock jitter) in a manner that is non-invasive to the circuit or node of interest. The signal jitter is measured by counting photon emissions at various nodes of interest across a controlled collapse chip connect (C4) mounted die, without interfering with the normal operation of the circuit of interest. This increases the precision and accuracy of the measurement of signal jitter significantly, since small amounts of phase noise on a particular clock signal edge can be detected. The emitted photons can be detected and subsequently correlated to a precise time base to obtain a statistical spread of switching events in time. The range of the photon distribution can be used to reliably determine safe and reasonable timing guard bands for clock and data paths in an IC.