An analytical procedure for estimating field lifetime and failure rate of electronic packages

To understand the reliability characteristics of electronic packages under field conditions, accelerated life tests (ALT) with higher stress levels are needed in practice. Instead of the time-consuming and costly ALT, an analytical procedure based on finite element simulation and a Weibull statistical method to estimate the lifetime and failure rate of electronic packages subjected to thermal cycling loadings is proposed in the present study. To consider uncertainties, geometric parameters and material properties are assumed as random variables and incorporated into numerical simulation. The result shows that the mean time to failure (MTTF) of a studied electronic package under a specific thermal cycling loading condition can be predicted accurately. From either the proposed analysis or based on a particular model found in literature, the acceleration factor (AF) can be predicted accurately as well. Furthermore, according to the outcome from the Weibull statistical method, the failure rate under either the field or a particular test condition can be determined. Accordingly, the MTTF and failure rate of the package under field conditions can be estimated from the result of a simulated accelerated test as well as the AF model. The present study indicates that the proposed analytical procedure can help engineers evaluate the reliability of electronic packages rapidly and effectively.