Condition indicators for reliability monitoring of microsystems

Information about the condition of electronic systems in use supports reliability, maintenance and safety. This paper describes an approach to condition monitoring using monitoring structures. With such structures, the remaining life time of a system can be estimated in field use under varying load. The design and evaluation of monitor structures sensible to thermo-mechanical load is shown. Technological boundaries are taken into consideration and an example of a flip chip based monitor structure is presented. The tailoring of the structure regarding the failure model is described in general and in detail. To achieve a robust structure, parametric finite element modeling of technological fabrication tolerance is carried out to determine the selectivity of the structures. Analyzing the results of the finite element study, conclusions concerning the statistical distribution of the failure are drawn and suggestions are made to improve the accuracy of condition monitoring.