The electronics industry is in the process of eliminating lead from all manufactured products because of the environmental hazards associated with lead. ExpressPCB fully supports this change. RoHS helps reduce damage to people and the environment in third-world countries where much of today’s “high-tech trash” ends up. The use of lead-free solders and components has provided immediate health benefits to electronics industry workers in prototype and manufacturing operations.
Though often referred to as the lead-free directive, RoHS is not limited in scope to lead alone. RoHS also restricts the use of these six substances:
- Lead (Pb)
- Mercury (Hg)
- Cadmium (Cd)
- Hexavalent Chromium (Cr6+)
- Polybrominated Biphenyls (PBB)
- Polybrominated diphenyl ether (PBDE)
More information on RoHS-compliant boards and the RoHS Directive can be found at https://www.gov.uk/guidance/rohs-compliance-and-guidance
We are convinced that immersion silver is the best RoHS compliant finish for the majority of our customers and their applications. Our testing has shown that silver gives the best solder joint of any of the other finishes tested.
Silver immersion plating has been on the market for over 10 years and end users have befitted from this finish long before RoHS requirements came into play. Silver, when stored properly, has a shelf life of 12 months (easily as long as OSP), and can withstand multiple heat cycles during assembly. Silver immersion does not require any special fluxes or solders and fits in perfectly with the “quick turn” mode of operation.
The contact resistance is very low and the co-planarity of the finish provides a completely flat surface for solder paste application on fine pitch devices.