When using/changing to lead-free solders, what are the implications for x-ray inspection?

Existing and future x-ray equipment will be able to see the faults generated by using lead-free materials, such as under BGA and CSPs, as well as within the rest of the SMT components. All that may be necessary is the adjustment of certain x-ray tube parameters, compared to those used for equivalent Sn/Pb products, to ensure the best image contrast is available to allow for easy analysis.

Further information on the implications for using x-ray inspection with lead-free materials can be found in the following technical papers presented by Dage at the Proceedings of SMTA International, Chicago, September 2003 - Implications Of Using Lead-Free Solders and at the Proceedings of SMTA International, Chicago, September 2004 - Does PCB Pad Finish Affect Voiding Levels In Lead-Free Assemblies