The Fluorescent Dye Penetrant test highlights leak pathways in hermetic and non hermetic devices. The test provides a definitive view of the leak paths including cracks, voids, delaminations and other fractures.
Microelectronic component manufacturers develop components designed to withstand the effect of time and environment. Whether the component is hermetic or not, protecting the active area inside the device is critical.
Glass Feedthrough Showing Fractures
The fluorescent dye penetrant test provides the means to understand failures due to packaging faults or assembly problems. This method is an investigation tool dedicated to the research of leak origins and mechanisms.
A typical application of Fluorescent Dye Impregnation is the inspection of the areas previously identified by Helium Sniff testing. It helps to visualize device faulty areas and establishes the source of hermeticity failure (ceramic/glass fracture, void in solder, plastic delamination, ...)
Glass Feedthrough Showing Void In Solder
The method consists in submerging the device into a fluorescent dye fluid which has the viscous properties to fill very fine cracks. Leak rates as low as 5.10-8 atm.cc/sec Helium have been effectively measured. After curing, the impregnated device is encapsulated in a transparent resin for cross-sectioning. A microscope inspection of cross-sections under ultraviolet light reveals the leak pathways.
Delamination of Lead Frame in a PEM's device