ABSTRACT
Electronic products have become more vulnerable to corrosion due to dense packaging and high-impedance circuitry. Encapsulating larger chips in smaller packages reduces design allowances for thermomechanical stability and protection from the environment; narrow electrical pathways and connections can tolerate very little corrosion before circuit function is impaired. The time to corrosion failure of a package is dependent on the time required for moisture ingress and the time it takes for the corrosion process to cause damage. The conductive path serves as a medium for transferring ions during the corrosion process. When the package is in storage without the benefit of operating heat to dissipate the electrolyte, the electrolyte continues to provide a conductive path for the corrosion, which occurs continuously. Galvanic corrosion arises from an extensive use of precious metals coupled with base metals in chips and packages. Crevice corrosion is a localized attack in a crevice between two metals or a metallic and a nonmetallic surface.
