OSP
OSP (=Organic Surface Protection), is a board surface and protects the copper surfaces of the pads from oxidization. OSP is an organic solution that is applied to the copper surfaces through a rinsing process or by submersion in an immersion bath. The resulting layer has the appearance of a clear lacquer, is transparent and can barely be seen on the copper. OSP is a lead-free alternative to HAL (Hot Air Leveling). Temperature and the activity of the flux are contributing to the removal of the OSP layer during soldering. OSP is not suitable for multiple soldering processes, resp. in a limited way when soldering takes place in an environment of cover gas.