Electronic device encapsulation using red phosphorus flame retardants

This paper presents an analysis of the use of red phosphorus as a flame retardant material in encapsulated microcircuits and discusses the reliability risks. Chemical reactions, which can arise when red phosphorus is exposed to ambient humidity to form highly mobile ions and oxygen-containing phosphorus acids, are presented. These ions and acids can induce electro-chemical migration, causing short circuits between leads and between wires, internal to the packaged device. Field failures caused by the red phosphorous flame retardant are also presented.