For certain customers we are planning a lead-free transition period. This means that orders can be produced lead-free or lead containing. Due to the lead-time for bare boards we order the boards lead-free and decide later if we will produce lead-free or not. Do you have any concerns or recommendations on reflow and wave soldering with HAL lead-free board finish with a lead containing process?

Reverse compatibility is not an issue. The HASL coating either SAC or SN100C will work fine with a tin lead process. If you are running a high volume manufacturing using SAC HASL you may want to set up an analytical service to monitor silver build up. With Sn100C that would not be necessary.

Karl Seelig Deck Street Consultants In his 32 years of industry experience, Mr. Seelig has authored over 30 published articles on topics including lead-free assembly, no-clean technology, and process optimization. Karl holds numerous patents, including four for lead-free solder alloys, and was a key developer of no-clean technology.