ICs and hybrid modules have become more and more reliable in recent years – and a catastrophic failure is now usually the result of the designer or user exceeding some Absolute Maximum Rating parameter of the part that failed – as opposed to “Infant Mortality”. ESD over-voltage damage from improper handling is a common culprit, as are un-planned-for voltage transients, over-temperature, or just plain making mistakes in the design application. There are no mysteries in electronics design – sometimes though, you just haven’t gathered enough data to understand a situation.
Re: tin Whiskering – The growth of tin sulfide whiskers on tinned component leads, and their effect on the solderability of the affected parts has been a major problem in military electronics for years. The problem results from the use of pure tin to plate solderable leads. When placed in proximity with a cardboard box or paper which is processed with acid, the outgassing of sulfur dioxide from the paper causes the growth of tin sulfide crystals, or “whiskers” on the plated surfaces. Soldering of the leads is then difficult or impossible, and failure of the soldered joint is not unusual. Most defense contractors have requirements in their specifications that the tin plating on component leads contain at least 3% lead in the alloy, in order to prevent whiskering. The problem becomes very tricky, as European ROHS standards prohibit the use of lead on component leads – so all the parts manufacturers are omitting lead from their plating process.