1. Basic Concepts in Reliability Design - nl3prc

[2] Designing for Reliability(5) OthersSince resin has a higher thermal resistance than metal, if thermal dissipation is inadequate, thechip temperature will increase, degrading operating margins or materials and causing the deviceto fail. To prevent this, countermeasures such as increasing the thermal conductivity of the resinor attaching heat sinks are taken.However, various failures can still occur if the ambient temperature or power dissipation exceedsthe absolute maximum rating.Plastic-encapsulated devices can ignite at extremely high temperatures. This can occur withseveral of the failure mechanisms described above. Toshiba are now making Flame-resistantresins which conform to the current standard for resin non-flammability contained in the U.S.Underwriter’s Lab Inc. (UL) Standard.2-41