Many in the component industry have reached a comfort level with tin alloy solder and finishes. They have become confident that combinations of silver and copper with pure tin will dampen the effect of tin whiskers, those tiny hairs that can grow on pure tin under stress and break off, potentially causing a short in the component and shutting down an entire system. Many blame tin whiskers for the failure of the $250 million Galaxy 4 communications satellite in 1998.
We quizzed engineers and found a major split on the issue. With the IPC releasing the preferred blend of tin, silver, and copper, many engineers in commercial electronics have become confident the tin whiskers problem is solved. But engineers in the aerospace and defense industries vehemently insist the testing used to validate the tin alloy was insufficient.
Perspective is everything. Tin whiskers can take up to two years – in some cases 20 years – to develop. If you’re building a cell phone, who cares. If you’re building a commercial airliner with a 25-year lifespan, you may have a problem.