(It usually works, but surprises abound)

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What? RoHS requires, amongst other things, the elimination of Pb from solder (links). Of course many remain exempt, at least for a while. However, if you plan to rely on your exemption for long, then you are probably kidding yourself. More...

Is lead free a problem? Supply chain, inventory control, legal, and other challenges are widely recognized. Lead free assembly as such is not difficult. Some have done it “without problems” for years. Yields don't have to be an issue. However...

Problems: Quality, Robustness, Reliability Assessment. Reproducibility and testing are concerns.

Damage to Component or PCB --Some effects of lead free HASL, mass reflows, wave solder, repair, and the harder joints are obvious. Others are easily missed. Most are not commonly tested for. More...
Solder Pad Finish Issues -- With one exception. all 'the usual' pad fragility problems are exacerbated, and 'new' intermetallic structures lead to additional ones. No common finish is immune to occasional disasters. More...
Pad 'Cratering' & IMC Failures -- Thermal cycling is not supposed to lead to IMC failure or pad 'cratering'. If it does, we do not try to assess
life, we fix the problem. Mechanical testing is another story, even without
problems or substrate damage. Lead free alloy selection may be less simple than it looks (more...)
Robustness & Reliability of Solder -- Most people are deceiving themselves when they test. If we would just switch to conductive adhesives, everybody would recognize how different the materials issues are. Dangerous misconceptions and surprises arise from implicitly treating the lead free solders as 'similar' of nature to SnPb. More...
Forward/Backward Compatibility -- It often works out, but disaster may strike any time. Don't do it unless you absolutely have to. If you think lead free is complex (it is), try mixing it with SnPb. More...
Whiskers-- Enormous efforts have been expended on the study of Sn whiskers without yet reaching a satisfactory resolution. More...

What can you do?

• Convince yourself you have all of the above under control (it's more complex than often recognized, and researching it will take you years).
• Keep an eye on this site. There is lots of content still to come.
• Can't wait? Need more? The public access part of this site will never give you more than an introduction, but you can get access to a lot more (click here).

Questions/Comments? Email us at borgesen@unovis-solutions.com.