Failure Analysis of a PROM at Low Temperature Induced by Process Deviation

This paper focus on failure analysis of a PROM at low temperature induced by process deviation. An abnormal pulse occurs from "0" to "1" of the reading data of the PROM at -10 °C. The failure mechanism of the PROM is analysed. By testing, the reference voltage of the comparator of the failure PROM is smaller than the normal PROM especially in the low temperature. The reference voltage gets smaller because of not only the NMOS but also the resistor, which result in the same reference voltage change trend with the decrease of the temperature. With the extremum of the process parameters, a simulation at different temperature is performed, which has the same waveform and the same failure temperature with the test. To avoid this failure, the maximum allowable deviation of the resistance of the resistor is 8% with the noise tolerance of 30 mV.