New Concerns About Integrated Circuit Reliability

In order to make sure we have the infant-mortality problem in perspective, let us take a look at Fig. 9. This shows the typical infant-mortality failure rate in digital bipolar integrated circuits compared to those resulting from the failure mechanisms typical of the main population. The range of the long-life main-population rates is suggested to be within realistic expectation, based on accelerated-stress tests on a variety of integrated-circuit types in recent years. It represents product which could pass a typical commercial life test of 1000 hours at 125°C. What is demonstrated is that, even though the long-life reliability of an integrated circuit could be quite satisfactory, infant mortality can provide failure rates which could be undesirable for many present-day equipments, for times which are significant with respect to equipment life. For example, the calculations from MIL-HBK-217 provide failure rates of SSI-MSI digital integrated circuits as about 10 to 100 FIT's, yet we see in Figure 6 that this failure rate is achieved only after from one month to one year of equipment operation.