Abstract

Very highly purified water such as De-ionized (DI) water tends to become very corrosive once exposed to the atmosphere. This “Hungry Water” as known in the water purification world is known to be a major source of corrosion [1]. The DI water was responsible for corrosion of tin during autoclave (pressure cooker) testing of Integrated Circuit (IC) devices assembled in plastic Quad Flat Package (QFP) with fine pitch leads. The copper leads of these packages are plated with solder. The copper leads of the packages are plated with solder composed of Lead and Tin. Due to the effect of corrosive water, Tin from solder corroded during the autoclave testing and formed thin whiskers of solder. These whiskers created a leakage path between the leads causing the devices to fail for pin to pin leakage.

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