How Getters Improve Hermetic Electronic Packages Reliability
Electronic components may fail if they are exposed to corrosive agents or chemical attack by moisture or other reactive gases that may be present within an electronic package or enclosure. The reliability of sensitive electronic components can be improved by hermetically sealing them within a protective enclosure and self-contained atmosphere.
While hermetic sealing may be effective, outgassing of the package materials or materials within the enclosure may be a source of reactive moisture or other gases that could contribute to early device failure. Generally speaking, an assembled package is baked out before hermetically sealing the enclosure under specific temperatures for a duration of a few hours to a few hundred hours in order to drive potential contaminants from the package materials or components prior to the final hermetic sealing process.
While this pre-bakeout process is most effective for metallic material, its efficiency to devolve all of the potential contaminants present within the device is less effective for polymeric based components, which may include epoxies and circuit boards. This may result in contaminants being outgassed into the sealed device during their operational life. In such cases, it may be necessary to install getters, which are passive materials that can remove:
- Moisture (H2O)
- Hydrogen(H2) Oxygen (O2)
- Carbon dioxide (CO2) Hydrocarbons (HCs)
- Volatile organic compounds (VOCs)
- Other products of outgassing
Electronic Systems Failure Modes
Sensitive electronic components may be subject to numerous failure modes if they are not hermetically sealed. The process of hermetic sealing ensures that there are no leak paths or channels by which external atmospheric gases or vapors may be transported into the enclosure over long periods of time, for example, 10 to 20 years.
Additional protection is added by evacuating the atmospheric air within the enclosure and replacing it with an inert atmosphere, such as pure nitrogen gas or nitrogen gas mixed with helium gas during the hermetic sealing process.
While hermetic sealing can be effective in many applications, certain package materials within the electronic system, such as polymers, epoxies, printed circuit boards and metal plating layers may outgas a variety of potential contaminants when subjected to operating temperature extremes.
These contaminants may react with internal electronic components resulting in corrosion and oxidation, or they may interfere with the regular operation of the electronic system, leading to reduced service life and premature failure of the electronic system.
To learn more about the dangers outgassing can present to high-reliability, electronics residing in a hermetic package and how HSG's getters safeguard against this threat, complete the form above and download the full Engineering Brief.