Immersion Tin: Pure tin deposition by dipping with a thickness of between 0.8 µm to 1.1 µm. Finishing is Lead Free and with RoHS compliant. Excellent flatness, recommended for complex SMD, Fine Pitch BGA, Press Fit and Multisolder. It can be stored up to 1 year. The main advantage is that it can be re-worked or re-freshed due to oxidation or storage expiration. The problem is the tin whiskers.
Material /Laminate: FR4 TG140
Board thickness: 1.6mm
Copper weight: 1/1/1/1oz
Finishing: Immersion Tin
The affect of surface treatment on soldering as below,