Getters and Design to Reliability: A Tool For Lifetime Assurance

摘要

The key to reaching multi-decade package lifetimes and device reliability is to not just take a snap shotwith a RGA and declaring a part passed per MIL-STD-883. It requires a deep understanding of the sources ofunwanted gases in a package, characterizing their true flow rates within, without and through the package system,and carefully choosing processes and materials, including getters, to manage the unwanted gases. This is truewhether the package is hermetic or non-hermetic.A multi-step process is discussed to include identifying the gas sources, the species present and theirquantities, modeling the true quantities of gas generated over the lifetime of the package, and removing it, eitherthrough process or materials. When package service lifetimes reach decades, traditional understandings start to fallapart and careful quantitative analysis is rewarded.Getters play a key role in attaining multi-decade lifetimes. Getter selection and sizing is discussed. Includedin the discussion will be a brief synopsis of the current state of the art of gettering technology.