The white plague is the intermetallic compound Au5Al2, which forms when gold wire bonds are attached to aluminum metallization on a silicon die at high temperatures. This compound is highly brittle and increases electrical resistance at the junction. Over time and thermal cycling, it leads to microcracking and complete mechanical failure of the chip's internal connections.
Heard on the job
The failure analysis report showed white plague at the wire bonds, explaining why the older chips kept dropping out under thermal load.
Insider tip
It is closely related to purple plague (AuAl2), another intermetallic compound that forms in the same gold-aluminum junctions and causes similar catastrophic failures.