A practical statistical technique to improve seal integrity and reliability of microelectronic packages

This paper presents insights into the variability of the functionality, quality and reliability characteristics of hermetically sealed packages for electronic applications. Process characterization and analysis methods are shown on packages from a true production environment. The concept of statistical models and filtering is given to depict the output variables (leak rate, residual gas analysis) and to define process leak limits derived from characterization instead of arbitrary limits set by military standards. Process monitoring (SPC) via statistical charts (standard deviation and median) maintains the on-going control. The leak limit set by process control totally eliminates fluid ingress in packages and moisture related corrosion failures compared to fixed military standard limits. This statistical technique is easy to implement and has potential usefulness in new applications such as assessing new methods and configurations of hermetically sealed enclosures. By preventing moisture induced corrosion, long term reliability is improved significantly