Integrated circuits failure modes

This section describes a methodical procedure that allows reliability issues to be approached efficiently. MEMS reveal specific reliability aspects, which differ considerably from the reliability issues of integrated circuits and macroscopic devices. A classification of typical MEMS-failure modes is given, as well as an overview of lifetime distribution models. The extraction of reliability parameters is a Tack of failures situation using accelerated aging and suitable models. In a case study, the implementation of the methodology is illustrated with a real-fife example of dynamic mechanical stress on a thin membrane in a hot-film mass-airflow sensor. 

As stated above, the technique requires that all failure modes of a component are known. This is all but impossible in complex VLSI integrated circuits like microprocessors. For these circuits an estimate can be made of various failure modes based on manufacturers life test data or failure mode handbooks. 

Unfortunately, the most difficult failure modes to analyse are sometimes also difficult to confirm through testing. For example, it is impossible to insert aU faults for most Integrated Circuits. Software packages may also be used to simulate failures, which allow the equivalent of the fault to be inserted into the circuit simulation and the failure effect determined. 

A piece-part FMEA is not practically feasible for modem microcircuit-based LRU and systems. Determining all the failure modes of any but the simplest components (where industry data is available) is extremely difficult and sometimes impossible (especially for integrated electronic circuits). 

Discrete Semiconductor Failure Modes Integrated Circuit... 

The failure modes of integrated circuits (IC) have already been illustrated in Chapter 5. Their significance is special for safety-related equipment since IC failure modes may be undefinable. Some basic terminology for IC failures is presented in Table 6.1. 

The conventional method for the reliability analysis of electronic systems is a component level failure mode and effect analysis (FMEA) which involves assessing the potential effects on the system of each mode of failure of each component. Because of the large numbers of components involved, the internal complexity of the integrated circuit components themselves and the time-dependence of internal states in a programmable system, this approach is impractical for the fuelling machine control system. 

Various failure and degradation mechanism have been identified that adversely impact the integrity of bolts used in safety related applications and in applications important to safety. Depending on the nature of the degradation mechanism a potential for common mode failures exists for same system or redundant system components. In addition, leaks from flanged joints represent a significant part of total number of leaks in primary circuit. 

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